Symmetrically dynamic equalized volume and pressure air management system

ABSTRACT

An air management system for a vehicle having a first pneumatic circuit and a second pneumatic circuit, in which the first and second pneumatic circuits are pneumatically connected in a neutral position via a cross-flow mechanism. The first pneumatic circuit includes a first leveling valve configured to adjust independently the height of a first side of the vehicle. The second pneumatic circuit includes a second leveling valve configured to adjust independently the height of a second side of the vehicle. The first and second leveling valves are configured to establish pneumatic communication between the first and second pneumatic circuits when the first leveling valve is not independently adjusting the height of the first side of the vehicle and the second leveling valve is not independently adjusting the height of the second side of the vehicle.

CROSS REFERENCE OF RELATED APPLICATION

This application claims the benefit under 35 U.S.C. § 119(e) of thefiling date of provisional patent application Ser. No. 62/520,918 filedJun. 16, 2017, provisional patent application Ser. No. 62/573,587 filedOct. 17, 2017, and provisional patent application Ser. No. 62/626,373filed Feb. 5, 2018, the disclosures of which are incorporated herein byreference in their entireties.

FIELD OF THE DISCLOSURE

This disclosure relates to improvements in air management systems forvehicles, trailers, and towables of any type, including load carryingprime mover and trailer vehicles having one or more axles supported byair springs.

BACKGROUND

Air suspension systems for vehicles have a plurality of air suspensionbags supporting one or more vehicle axles in pairs on either side ofeach axle. In one well-known vehicle, the pairs of air springs areconnected by a common large diameter air lines extending betweencorrespondingly positioned air springs on adjacent axles. The common airlines are each connected by an air line to a height control valvedirected to a respective side of a vehicle. The height control valvecontrols the air supply to the common air lines to adjust the inflationof the air springs to ensure that the vehicle is kept level as it isdriven over variable road conditions. Unless defined otherwise, the term“height control valve” is used as equivalent to the term “levelingvalve,” such that the terms “height control valve” and “leveling valve”may be used inter-changeably.

For example, when a vehicle negotiates a turn, the vehicle's center ofgravity shifts along its width away from the turn. Due to the weightshift, the air springs on the side of the vehicle facing away from theturn start to contract, while the air springs on the side of the vehiclefacing the turn start to extend. Consequently, the vehicle becomesunleveled from side-to-side. In response, one of the leveling valves onthe lowered side of the vehicle supplies air to the contracted airsprings, while the other leveling valve on the elevated side of thevehicle removes air from the extended air springs to keep the vehiclelevel. Through testing, it has now been found that leveling valves oftenovercompensate in responding to dynamic weight shifts of the vehicle, inwhich the air springs that were supplied air from the leveling valvetend to have a greater air pressure than the air springs that werepurged by the leveling valve. As a result, a pressure differencepersists between the two sides of the air suspensions system ever afterthe leveling valves attempt to level the vehicle. Even though a pressuredifferential remains between the air springs on opposite sides of thevehicle, the leveling valves return to a neutral mode (e.g., the rotarydisk is set within a dead band range), in which there is a lack ofpneumatic communication between the air springs on opposite sides of thevehicle. Due to this pressure differential between the air springs, thevehicle remains unlevel even after the leveling valves have adjusted thepressure of the air springs in response to the vehicle weight shift.

Other types of air suspension systems have replaced mechanical levelingvalves with electronic-actuated valves to the control the height of theair bags. While some electronic-actuated valves have been designed torespond to vehicle weight shifts or vehicle rolling, electronic-actuatedvalves fail to account for pressure differentials between the airsprings that persist after the heights of the air springs have beenadjusted in response to vehicle weight shifts.

Accordingly, the present inventors have recognized that there is a needfor an air management system that solves the problem of persistentpressure imbalance so that the vehicle may be restored to equilibriumair pressure, level and ride height.

SUMMARY

The present invention provides for an enhanced pneumatic suspensionsystem for a vehicle in which the air management system includes a firstpneumatic circuit, a second pneumatic circuit, and a cross-flowmechanism pneumatically connecting the first pneumatic circuit with thesecond pneumatic circuit. The first pneumatic circuit includes a firstleveling valve configured to adjust independently the height of a firstside of the vehicle. The second pneumatic circuit includes a secondleveling valve configured to adjust independently the height of a secondside of the vehicle. The first and second leveling valves are configuredto establish pneumatic communication between the first and secondpneumatic circuits when the first leveling valve is not independentlyadjusting the height of the first side of the vehicle and the secondleveling valve is not independently adjusting the height of the secondside of the vehicle. According to the various examples of the airmanagement systems described herein, all air management systems areamenable to modification such that each air management system may beutilized under mechanical or electronic operations (e.g., an actuatorfor a leveling valve may be switched from a mechanical mechanism to anelectronic component).

The first pneumatic circuit includes a first set of air springs disposedon a first side of the vehicle, a first supply tank, a first pluralityof air lines pneumatically connecting the first set of air springs withthe first leveling valve, and a first supply line pneumaticallyconnecting the first leveling valve with the first supply tank. Thesecond pneumatic circuit includes a second set of air springs disposedon a second side of the vehicle, a second supply tank, a secondplurality of air lines pneumatically connecting the second set of airsprings with the second leveling valve, and a second supply linepneumatically connecting the second leveling valve with the secondsupply tank. The cross-flow connections extend from the first levelingvalve to the second leveling valve. In another example, the first andsecond pneumatic circuits may be supplied air by a common air supplytank such that the air management system only includes only one airsupply tank to provide air flow to air springs on both sides of thevehicle. In one example, the first plurality of air lines and the secondplurality of air lines may be of substantially the same diameter andlength, and the first supply line and the second supply line may be ofsubstantially the same diameter and length.

In one configuration, each leveling valve may include a housing and acontrol arm pivotably connected to the leveling valve, in which thecontrol arm is configured to pivot between a neutral position and one ormore response positions in response to compression or extension of theair springs. The first and second leveling valves may be configured toestablish pneumatic communication between the first and second pneumaticcircuits when the control arm of both the first and second level valvesare set in the neutral position. The first and second leveling valvesmay be configured to prevent pneumatic communication between the firstand second pneumatic circuits when the control arm of one of the firstand second leveling valves is set to the one or more response positions.The first and second leveling valves may include a control arm sensorconfigured to detect the position of the control arm. The air managementsystem may include a control unit in electrical communication with eachcontrol arm sensor. Each control arm sensor may be configured totransmit the position of the control arm as a control arm position inputto the control unit. The control unit may be configured to determine avehicle height relative to the axle at the first and second sides of thevehicle based on the control arm position input.

In one example, the first and second leveling valves may each be arotary valve comprising a housing body and a rotary disk configured torotate within the housing body to alter communication between thebetween the first and second pneumatic circuits. Each housing body maycomprise a supply port configured to receive air from an air source, anexhaust port configured to exhaust air into an atmosphere, one or morespring ports configured to receive or supply air to one of the first orsecond pneumatic circuits, and a cross-flow port configured to receiveor supply air to one of the first or second leveling valves. In oneconfiguration, the rotary disk may be configured to establishcommunication between the one or more spring ports and the cross-flowport while neither establishing communication between the one or morespring ports and the supply port nor the one or more spring ports andthe exhaust port. In one configuration, the first and second levelingvalves may each comprise a control arm pivotably connected to thehousing body and configured to rotate about the valve in response to aheight change by one of the first or second pneumatic circuits. In oneconfiguration, rotation of the control arm may induce the rotary disk torotate between a plurality of angular positions to alter communicationbetween the supply port, the exhaust port, the one or more spring ports,and the cross-flow port.

In one example, the first and second leveling valves may each include amanifold housing, a valve element disposed in a bore of the manifoldhousing, and an electronic actuator. The valve element may be configuredto move in the bore of the manifold housing to one or more positionsincluding at least a neutral position to establish pneumaticcommunication between the first and second pneumatic circuits and asupply position to supply air to a respective pneumatic circuit from anair supply tank, and an exhaust position to remove air from therespective pneumatic circuit into the atmosphere. The electronicactuator is configured to trigger movement of the plunger between theone or more positions. The valve element may be selected from the groupconsisting of a plunger, a rotary disk, and a poppet. The electronicactuator is, e.g., a solenoid, a servomotor, and a stepper motor.

In one example, the air management system may include a control modulein electrical communication with the electronic actuator of eachleveling valve. The control module may be configured to transmit acommand to each electronic actuator to trigger movement of the valveelement between the neutral, supply, and exhaust positions. The airmanagement system may include one or more leveling sensors. Eachleveling sensor may be configured to detect a vehicle height relative tothe axle along a position of the vehicle and transmit the detectedvehicle height to the control module as a vehicle leveling input. Thecontrol module may be configured to determine a vehicle height relativeto the axle at the first and second sides of the vehicle based on thevehicle leveling input.

In one configuration each leveling valve may include acylindrical-shaped manifold, a valve member disposed in the manifold andin sliding engagement with an interior surface of the manifold, and anelectronic actuator operatively linked to the valve member. The manifoldmay comprise a plurality of openings disposed along a side surface ofthe manifold. The electronic actuator may be configured to actuate thevalve member to slide along the longitudinal axis of the manifold tocontrol the exposure of the plurality of openings such that a respectiveleveling valve is configured to selectively: (i) supply air to arespective pneumatic circuit, (ii) remove air from a respectivepneumatic circuit, or (iii) establish cross-flow between the first andsecond pneumatic circuits.

The present invention includes a leveling valve. The leveling valve maycomprise an upper housing mounted on a lower housing to form a valvebody, in which the valve body defines a chamber extending between theupper housing and the lower housing. The lower housing may include aplurality of ports communicating with the chamber, in which theplurality of ports include a supply port, an exhaust port, one or morespring ports, and a cross-flow port. In one configuration, the lowerhousing may further comprise a dump port, wherein the cross-flow port isdisposed on a first end of the lower housing and the dump port isdisposed on a second end of the lower housing opposite to the first end.In one configuration, the supply port may be disposed on a first side ofthe lower housing, and the exhaust port may be disposed on a second sideof the lower housing opposite to the first side of the lower housing. Inone configuration, the cross-flow port may be disposed on a first end ofthe lower housing, and the first end may extend between the first andsecond sides of the lower housing. In one configuration, the one or morespring ports may comprise a first spring sport located on one of thefirst side or the second side of the lower housing. The leveling valvemay include a control arm having a first end attached to a shaftextending through an upper surface of the upper housing, in which thecontrol arm is configured to rotate about the valve body in response toextension or compression of the vehicle suspension. The leveling valvemay include a rotary disk positioned in the chamber of the valve bodyand connected to the control arm by the shaft extending through theupper housing, in which the rotary disk is configured to rotate aboutthe supporting element within the chamber of the valve body. The rotarydisk may be configured to establish pneumatic communication between theone or more spring ports and the cross-flow port while neitherestablishing pneumatic communication between the one or more springports and the supply port nor the one or more spring ports and theexhaust port.

The present invention may include a method for controlling stability ofa vehicle. The method may comprise the step of providing an airmanagement system comprising a first a first pneumatic circuit and asecond pneumatic circuit. The first pneumatic circuit may include afirst leveling valve configured to adjust independently the height of afirst side of the vehicle. The second pneumatic circuit may include asecond leveling valve configured to adjust independently the height of asecond side of the vehicle. The air management system may include across-flow line connecting the first leveling valve with the secondleveling valve. The method may comprise the step of establishing, by thefirst and second leveling valves, pneumatic communication between thefirst and second pneumatic circuits when the first leveling valve is notindependently adjusting the height of the first side of the vehicle andthe second leveling valve is not independently adjusting the height ofthe second side of the vehicle.

The present invention may include a method for adjusting air pressure ofan air management system of a vehicle comprising one or more air supplytanks, a first pneumatic circuit disposed on a first side of thevehicle, and a second pneumatic circuit disposed on a second side of thevehicle. The method may comprise a step of adjusting independently theair pressure of the first pneumatic circuit by a first leveling valvesuch that the first leveling valve is either supplying air from the oneor more air supply tanks to the first pneumatic circuit or removing airfrom the first pneumatic circuit to the atmosphere. The method maycomprise the step of adjusting independently the air pressure of thesecond pneumatic circuit by a second leveling valve such that the secondleveling valve is either supplying air from the one or more air supplytanks to the second pneumatic circuit or removing air from the secondpneumatic circuit to the atmosphere. The method may comprise the step ofestablishing pneumatic communication between the first pneumatic circuitand the second pneumatic circuit only when both the first leveling valveand the second leveling valve are set in a neutral mode such that eachleveling valve is neither supplying air from the one or more air supplytanks or removing air into the atmosphere.

The present invention may include a control unit associated with an airspring of an air management system for a vehicle. The control unit maycomprise a housing configured to be mounted to a top plate of the airspring, wherein the housing comprises a valve chamber. The control unitmay comprise a valve disposed in the valve chamber. The valve may beconfigured to switch between a plurality of modes including: (i) anactive mode wherein the valve is adjusting independently a height of theassociated air spring, and (ii) a neutral mode wherein the valve isestablishing pneumatic communication between the associated air springand a cross-flow line connected to a second air spring of the airmanagement system when the valve is not in the active mode. The controlunit may comprise one or more sensors configured to monitor at least onecondition of the air spring and generate a measurement signal indicatingthe at least one condition of the air spring. The control unit maycomprise a communication interface configured to transmit and receivedata signals to and from a second control unit associated with thesecond air spring of the air management system. The control unit maycomprise a processing module operatively linked to the valve, the one ormore sensors, and the communication interface, wherein the processingmodule is configured to: (i) receive measurement signals from the one ormore sensors and data signals from the communication interface, and (ii)actuate the valve to switch between the active mode and the neutral modebased on the received measurement signals from the one or more sensorsand the data signals from the communication interface.

The present invention may include an air management system for avehicle. The air management system may comprise a first pneumaticcircuit having one or more air springs disposed at a first side of avehicle. The air management system may comprise a second pneumaticcircuit having one or more air springs disposed on a second side of avehicle. The air management system may comprise one or more cross-flowlines, wherein each cross-flow line extends from an air springassociated with the first pneumatic circuit to an air spring associatedwith the second pneumatic circuit. Each air spring may comprise acontrol unit. Each control unit may comprise a housing configured to bemounted to a top plate of an associated air spring, wherein the housingcomprises a valve chamber. Each control unit may comprise a valvedisposed in the valve chamber, wherein the valve is configured to switchbetween a plurality of modes including: (i) an active mode wherein thevalve is adjusting independently a height of the associated air spring,and (ii) a neutral mode wherein the valve is establishing pneumaticcommunication between the associated air spring and a respectivecross-flow line when the valve is not in the active mode. Each controlunit may comprise one or more sensors configured to monitor at least onecondition of the associated air spring and generate a measurement signalindicating the at least one condition of the associated air spring. Eachcontrol unit may comprise a communication interface configured todirectly transmit and receive data signals to and from other controlunits associated with other air springs of the air management system.Each control unit may comprise a processing module operatively linked tothe valve, the one or more sensors, and the communication interface,wherein the processing module is configured to: (i) receive measurementsignals from the one or more sensors and data signals from thecommunication interface, and (ii) actuate the valve to switch betweenthe active mode and the neutral mode based on the received measurementsignals from the one or more sensors and the data signals from thecommunication interface.

The present invention may include a method for controlling the stabilityof a vehicle comprising an air management system, in which the airmanagement system may comprise a first pneumatic circuit having one ormore air springs disposed at a first side of a vehicle, a secondpneumatic circuit having one or more air springs disposed on a secondside of a vehicle, and one or more cross-flow lines, in which eachcross-flow line extends from an air spring associated with the firstpneumatic circuit to an air spring associated with the second pneumaticcircuit. The method may comprise the step of monitoring, by a heightsensor and an air pressure sensor, a height and an air pressure of arespective air spring. The method may comprise the step of generating,by the height sensor and the air pressure sensor, a signal indicatingthe height and the air pressure of the respective air spring. The methodmay comprise the step of receiving, by a processing module, the signalindicating the height and the air pressure of the respective air spring.The method may comprise the step of calculating, by the processingmodule, a height differential rate and pressure differential rate of therespective air spring based on the received signal indicating the heightof the respective air spring. The method may comprise the step ofdetermining, by the processing module, whether to adjust the height ofthe air spring independently or establish pneumatic communicationbetween the air spring and a respective cross-flow line. The method maycomprise the step of actuating, by the processing module, a valve toswitch to one of the modes: (i) an active mode wherein the valve isadjusting independently a height of the associated air spring, and (ii)a neutral mode wherein the valve is establishing pneumatic communicationbetween the associated air spring and a respective cross-flow line whenthe valve is not in the active mode. In one configuration, the heightsensor, processing module, and the valve are disposed in a chamber ofthe air spring.

According to the various examples of the air management systemsdescribed herein, all air management systems include at least twoindependent pneumatic circuits, in which each independent pneumaticcircuit is configured to adjust independently the height of one side ofvehicle in response to dynamic vehicle weight shifts. In a state ofadjusting independently the height of one side of the vehicle, therespective pneumatic circuit is not in pneumatic communication with theother pneumatic circuit disposed on the opposite of the vehicle suchthat the air springs on one side of the vehicle are not in pneumaticcommunication with air springs disposed on the opposite side of thevehicle. According to the various examples of the air management systemsdescribed herein, all air management systems may selectively establishcross-flow between the two independent circuits so that the air springsdisposed on one side of the vehicle are in pneumatic communication withthe air springs disposed on the other side of the vehicle when all theleveling valves are set in a neutral position or neutral mode. In thepresent context, the leveling valve is set in a neutral position orneutral mode when leveling valve is neither supplying air from the airsupply tank to the air springs nor purging air from the air springs tothe atmosphere (e.g., the rotary disk is set within a dead band range).

Other features and characteristics of the subject matter of thisdisclosure, as well as the methods of operation, functions of relatedelements of structure and the combination of parts, and economies ofmanufacture, will become more apparent upon consideration of thefollowing description and the appended claims with reference to theaccompanying drawings, all of which form a part of this specification,wherein like reference numerals designate corresponding parts in thevarious figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated herein and form partof the specification, illustrate various embodiments of the subjectmatter of this disclosure. In the drawings, like reference numbersindicate identical or functionally similar elements.

FIG. 1A is a schematic view of an air management system according to oneconfiguration of the present invention. FIG. 1B is a schematic view ofan air management system comprising leveling valves disposed at acentral portion of a vehicle according to one configuration of thepresent invention. FIG. 1C is a schematic view of an air managementsystem comprising leveling valves, in which each leveling valve has aplurality of air bag ports, according to one configuration of thepresent invention.

FIG. 2 is a top view of a leveling valve according to one configurationof the present invention.

FIG. 3 is a perspective of a leveling valve according to oneconfiguration of the present invention.

FIG. 4 is an exploded view of a leveling valve according to oneembodiment of the present invention.

FIG. 5 is a perspective of a lower housing according to an embodiment ofthe present invention.

FIGS. 6A-6C are schematic views of a rotary disk according to anembodiment of the present invention.

FIG. 7 is a schematic view of an air management system according to thepresent invention.

FIG. 8 is a schematic view of an air management system according to thepresent invention.

FIG. 9 is a schematic view of an air management system according to thepresent invention.

FIG. 10 is a perspective view of a lower housing according to thepresent invention.

FIG. 11 is a top view of a lower housing according to the presentinvention.

FIG. 12A is a top cross-sectional view of the lower housing taken alongline Z-Z according to the present invention. FIG. 12B is a sidecross-sectional view of the lower housing taken along line Y-Y accordingto the present invention, FIG. 12C is a side cross-sectional view of thelower housing taken along line X-X according to the present invention.

FIG. 13 is a top view of a rotary disk according to the presentinvention.

FIG. 14A is a perspective view of a first poppet to be used in thepresent invention.

FIG. 14B is a cross-sectional view taken along line B-B of the firstpoppet to be used in the present invention.

FIG. 15A is a perspective view of a second poppet according to thepresent invention. FIG. 15B is a cross-sectional view taken along lineC-C of the second poppet according to the present invention.

FIG. 16 is a schematic view of an air management system according to thepresent invention.

FIG. 17 is a schematic view of an air management system according to thepresent invention.

FIG. 18 is a schematic view of an air management system according to thepresent invention.

FIG. 19 is a schematic view of an air management system according to thepresent invention.

FIG. 20 is a schematic view of an air management system according to thepresent invention.

FIG. 21A is a schematic view of an air management system according tothe present invention.

FIG. 21B is a schematic view of an air management system according tothe present invention.

FIG. 22 is a schematic view of a control unit according to the presentinvention.

FIG. 23 is a schematic view of a system controller according to thepresent invention.

FIG. 24 is a schematic view of a control unit according to the presentinvention.

FIG. 25 is a schematic view of a system controller according to thepresent invention.

FIG. 26A is a schematic view of a valve according to the presentinvention.

FIG. 26B is a cross-section view of a valve according to the presentinvention taken along line A in FIG. 26A.

FIG. 27 is a top perspective view of a lower housing according to thepresent invention.

FIG. 28 is a bottom perspective view of a lower housing according to thepresent invention.

FIG. 29 is an end view of a lower housing according to the presentinvention.

FIG. 30 is a side view of a lower housing according to the presentinvention.

FIG. 31 is a top plan view of a lower housing according to the presentinvention.

FIG. 32 is a bottom plan view of a lower housing according to thepresent invention.

FIG. 33 is a perspective view of a rotary disk according to the presentinvention.

FIG. 34 is a top plan view of a rotary disk according to the presentinvention.

FIG. 35 is a side view of a rotary disk according to the presentinvention.

FIG. 36 is a side cross-sectional view of a rotary disk according to thepresent invention taken along line 36 in FIG. 34.

FIGS. 37 and 38 are perspective views of a shaft according to thepresent invention.

FIG. 39 is a side view of a shaft according to the present invention.

FIG. 40 is a bottom end view of a shaft according to the presentinvention.

FIG. 41 is a top end view of a shaft according to the present invention.

FIG. 42 is a side view of a shaft according to the present invention.

FIG. 43 is a graph showing the air pressure of the various valve portsat various operation stages of the leveling valve according to thepresent invention.

FIG. 44 is a flow chart illustrating a method for adjusting air pressureof an air management system comprising first and second pneumaticcircuits according to the present invention.

DETAILED DESCRIPTION

While aspects of the subject matter of the present disclosure may beembodied in a variety of forms, the following description andaccompanying drawings are merely intended to disclose some of theseforms as specific examples of the subject matter. Accordingly, thesubject matter of this disclosure is not intended to be limited to theforms or embodiments so described and illustrated.

The present disclosure includes an air management system for a vehiclehaving a first pneumatic circuit having a first leveling valveconfigured to adjust independently the height of a first side of thevehicle, a second pneumatic circuit having a second leveling valveconfigured to adjust independently the height of a second side of thevehicle, and a cross-flow mechanism connecting the first leveling valvewith the second leveling valve. The first and second leveling valvesestablish pneumatic communication between the first and second pneumaticcircuits when the first leveling valve is not independently adjustingthe height of the first side of the vehicle and the second levelingvalve is not independently adjusting the height of the second side ofthe vehicle, e.g., when the ride height control arms on both sides ofthe vehicle are in a neutral position or when an electronic-actuatedvalve is set in a neutral mode. The first and second leveling valves areconfigured to be set to the neutral position or neutral mode under alldriving conditions including when the vehicle is traveling at a velocitysubstantially above zero miles-per-hour.

As used herein, the terms “neutral position” and “neutral mode” aredefined as the state in which neither leveling valve is supplying airfrom the air supply tank to the air springs or removing air from the airsprings to the atmosphere, and each of the leveling valves are inpneumatic communication with each other.

As used herein, the term “active mode” is defined as the state in whichthe valve is independently adjusting the height or air pressure of oneor more air springs in one pneumatic circuit while the valve is not inpneumatic communication with any components of another pneumaticcircuit.

As used herein, a “cross-flow mechanism” or “cross-flow system” includesany components necessary to establish pneumatic communication between afirst pneumatic circuit and a second pneumatic circuit, wherein thefirst and second pneumatic circuits are provided on opposite sides of avehicle, i.e., left and right sides. The cross-flow mechanism orcross-flow system may include a cross-flow air line connecting a firstleveling valve and a second leveling valve connected to a cross-flowport on each leveling valve, in which the cross-flow air line is notdirectly connected to a supply tank or a supply line connected to thesupply tank. The cross-flow mechanism or cross-flow system may alsoinclude a cross-flow controller device connected to each of the firstleveling valve and the second leveling valve. The cross-flow mechanismor cross-flow system may also include electrical sensors, e.g., airpressure sensors, air flow sensors, ride height sensors, stabilitycontrol sensors.

As used herein, the “response position” is defined as the state in whichone or more leveling valves on each side of the vehicle are adjustingthe air pressure of air springs independently in the pneumatic circuits.

As used herein, “dead band” refers to range of rotation in which a disksurface of a rotary disk completely overlies the reservoir cavity of thelower housing such that the leveling valve is neither supplying air fromthe air supply tank to the air springs or removing air from the airsprings to the atmosphere.

In one example, each leveling valve includes a housing, a valve elementdisposed in a bore of the housing, and a control arm pivotably connectedto the housing such that it pivots from a neutral position to one ormore response positions to induce rotation or movement of the valveelement. In another example, each leveling valve includes a housing anda ride height sensor electrically connected thereto instead of a controlarm. In another example, each leveling valve includes a housing, a valveelement disposed in a bore of the housing, a control arm pivotablyconnected to the housing to induce movement or rotation of the valveelement, and a sensor disposed in the housing to detect movement of thecontrol arm. In another example, each leveling valve may include ahousing, a valve element, and a motor (e.g., stepper motor) to inducerotation or movement of the valve element. The valve element may beselected from the group consisting of a plunger, a rotary disk, and apoppet.

In one example, the first and second leveling valves establish pneumaticcommunication between the first and second pneumatic circuits when thecontrol arm of both the first and second level valves are set in theneutral position, and the first and second leveling valves areconfigured to prevent pneumatic communication between the first andsecond pneumatic circuits when the control arm of one of the first andsecond leveling valves is set to the one or more response positions.

In one example, the first pneumatic circuit includes a first set of airsprings disposed on a first side of the vehicle, a first supply tank, afirst plurality of air lines pneumatically connecting the first set ofair springs with the first leveling valve, and a first supply linepneumatically connecting the first leveling valve with the first supplytank; and the second pneumatic circuit includes a second set of airsprings disposed on a second side of the vehicle, a second supply tank,a second plurality of air lines pneumatically connecting the second setof air springs with the second leveling valve, and a second supply linepneumatically connecting the second leveling valve with the secondsupply tank. In another example, the first and second pneumatic circuitsmay be supplied air by a common air supply tank such that the airmanagement system only includes only one air supply tank to provide airflow to air springs on both sides of the vehicle.

In one example, the air lines are provided to supply equal volumes ofair to maintain symmetry within the pneumatic circuits on both sides ofthe vehicle. The air lines are of substantially the same (e.g., within±10% or ±5% or ±2% or ±1%) or equal diameter and/or length. The supplylines are of substantially the same (e.g., within ±10% or ±5% or ±2% or±1%) or equal diameter and/or length.

FIGS. 1A-C show configurations of air management systems for a vehicleas disclosed herein, indicated by reference number 100. The airmanagement assembly 100 includes a first pneumatic circuit disposed on afirst side of a vehicle 1, a second pneumatic circuit disposed on asecond side of the vehicle 1, and a cross-flow line 38 pneumaticallyconnecting the first and second pneumatic circuits. The vehicle 1 canhave front and rear driven and/or non-driven wheeled axles 2 and 3,which are supported in a known manner on the chassis 1 by pairs of airbags (also referred to interchangeably as air springs) 4 and 5, 6 and 7,8 and 9 and 10 and 11, positioned as illustrated on either side of theaxles 2 and 3. The present invention is not limited to having theparticular number of axle(s), air bags (air springs), air lines/hoses,air supply tank(s) that are shown in the drawings, as these elementsvary depending on the type of vehicle that is used as would beimmediately clear to a person skilled in the art. In another example,the first and second pneumatic circuits may be supplied air by a commonair supply tank such that the air management system 100 only includesonly one air supply tank to provide air flow to air springs 4-11 on bothsides of the vehicle 1.

In FIGS. 1A-C, air springs 4, 5, 8, and 9 are positioned on the firstside of the vehicle 1 and connected together by separate air lines 12,13, and 18-21 to form a first set of air springs. Air springs 4, 5, 8and 9 and separate air lines 12, 13, and 18-21 are supplied air by avalve hose 28, which is connected to a first leveling valve 16. A supplyhose 30 extends directly from the first leveling valve 16 to a firstsupply tank 32 for supplying air to the first leveling valve 16. Thesupply hose 30 is also provided with a pressure protection valve 34.Accordingly, air springs 4, 5, 8, and 9, separate air lines 12, 13, and18-21, valve hose 28, first leveling valve 16, supply hose 30, pressureprotection valve 34 (not required in some vehicles or air managementsystems), and the first supply tank 32 form the first pneumatic circuitadapted for adjusting independently the height of the first side of thevehicle 1.

In some embodiments (not shown), the air management assembly 100 maycomprise a single air supply tank to deliver air simultaneously to boththe first and second pneumatic circuits and a single pressure protectionvalve connected to the air supply tank by a single hose and connected tothe first and second pneumatic circuits through two supply hoses. Thesingle pressure protection valve is configured to supply sufficient airpressure to both the first and second pneumatic circuits in the event ofa leak or failure within the air management system 100. The singlepressure protection valve is configured to have a larger air capacity tothe dual pressure protection valves 34 in order to provide sufficientair to both the first and second pneumatic circuits simultaneously.

Air springs 6, 7, 10, and 11 are positioned on a second side of thevehicle 1 and connected together by separate air lines 14, 15, and 22-25to form a second set of air springs. Air springs 6, 7, 10, and 11 andseparate air lines 14, 15, and 22-25 are supplied air by a valve hose29, which is connected to a second level valve 17. A supply hose 31extends directly from the second leveling valve 17 to a second supplytank 33 for supplying air to the second leveling valve 17. The supplyhose 31 is also provided with a pressure protection valve 35.Accordingly, air springs 6, 7, 10, 11, separate air lines 14, 15, and22-25, valve hose 29, second leveling valve 17, supply hose 31, thepressure protection valve 35, and the second supply tank 33 form thesecond pneumatic circuit adapted for adjusting independently the heightof the second side of the vehicle 1. Both the first pneumatic circuitand the second pneumatic circuit are independently operable so that thefirst leveling valve 16 independently delivers air to or purges air fromthe first side of the vehicle 1 and the second leveling valve 17independently delivers air to or purges air from the second side ofvehicle 1.

To ensure a balanced supply air of substantially the same volume andpressure to each air spring, the separate air lines 12, 13, and 18-21 onthe first side of the vehicle 1 and the separate air lines 14, 15, and22-25 on the second side of the vehicle 1 are of substantially the samesize (internal diameter) and length. In the illustrated configuration,the separate air lines 18-21 and 22-25 each have a bore diameter ofabout 12 mm (½ inch). Other sizes may be used with similar resultsprovided the size and length of the air lines in each set or group (e.g.18 to 25, 28 and 29, 30 and 30 31 etc.) are the same. For similarreasons, the valve hoses 28 and 29 are of substantially the same size orinternal diameter and length, and the supply hoses 30 and 31 are ofsubstantially the same size or internal diameter and length. Theprovision of the separate air lines 18-21 and 21-25 and the connectionof these lines to the separately supplied leveling valves 16 and 17ensure that an equal volume of air is rapidly supplied to each of theair springs so that the internal pressure of the air springs respondappropriately to changes in road conditions relayed to the valves 16 and17. Thus, the rate of change for the internal pressure of the first setof air springs is substantially symmetrical to the rate of change forthe internal pressure of the second set of air springs.

The first control valve 16 and the second control valve 17 each includecontrol arms 16 a, 17 a linked to a rigid bar 36 mounted underneath theair springs 9 and 11. The control arms 16 a, 17 a are each configured tomove up and down in response to compression and extension of the airsprings, which actuates the first and second control valves 16, 17 toeither supply or purge air to and from the air springs. Both the firstand second leveling valves 16, 17 neither supply air from the supplytank to the air springs nor remove air from the air springs to theatmosphere when the control arms 16 a, 17 a are in a neutral position. Across-flow line 38 extends from the first leveling valve 16 to thesecond leveling valve 17 to connect the first and second levelingvalves. As shown in FIG. 1A, the cross-flow line 38 is not directlyconnected supply lines 30, 31 or the air supply tanks 32, 33. When thecontrol arms 16 a, 17 a are both in the neutral position, the first andsecond leveling valves 16, 17 are in pneumatic communication with eachother such that there is pneumatic communication between the first andsecond pneumatic circuits via the cross-flow line 38 to equalize airpressure between air springs 4, 5, 8, and 9 on the first side of thevehicle 1 and air springs 6, 7, 10, 11 on the second side of thevehicle. As a result, the first and second pneumatic circuits are linkedtogether as a common circuit when the control arms 16 a, 17 a are bothin the neutral position. By maintaining equal air pressure between thefirst and second sets of air springs, the first and second levelingvalves 16, 17 equilibrate the pressure between the two sides of thevehicle when both control arms 16 a, 17 a are in the neutral position.In the illustrated embodiment, only a single cross-flow line 38 isneeded to establish pneumatic communication between the first and secondpneumatic circuits such that air flows between the left and right sidesof the vehicle.

The first and second leveling valves 16, 17 only permit pneumaticcommunication with each other via the cross-flow line 38 when thecontrol arms 16 a, 17 a are both in the neutral position. In otherwords, the first and second leveling valves 16 a, 17 a prevent pneumaticcommunication between the first and second pneumatic circuits wheneither one of the control arms 16 a, 17 a is not in the neutralposition. By not establishing communication between the first and secondpneumatic circuits when either one of the control arms 16 a, 17 a aremoving up and down from the neutral position, the first and secondleveling valves 16, 17 are able to purge air from or supply air to theair springs independently. Accordingly, when the vehicle 1 isnegotiating a sharp turn that shifts the vehicle's center of gravity,one of the first and second leveling valves 16, 17 supplies air to theset of air springs that have been contracted from the weight shift ofthe vehicle 1, while the other one of the first and second levelingvalves 16, 17 purges air from the other set of air springs that havebeen extended from the weight shift of the vehicle without anycross-flow between the first 16 and second 17 leveling valves. In thisstate, the first and second leveling valves 16, 17 may overcompensatefor the dynamic weight shift of the vehicle by either supplying too muchair to one set of air springs or removing too much air from the otherset of air springs, resulting in a slight pressure difference betweenthe first and second sets of air springs. This slight pressuredifference between the first and second sets of air springs may nottrigger either control arm 16 a, 17 a to pivot away from the neutralposition as the vehicle 1 pulls away from the turn, which would keep thevehicle 1 in an unlevel state if not for the mechanism described in thepresent disclosure. According to the present disclosure, because thefirst and second leveling valves 16, 17 communicate with each other whenboth control arms 16 a, 17 a are in the neutral position via cross-flow38, the slight pressure difference between first and second sets of airsprings is eliminated as air passes via the cross-flow line 38 from theset of air springs at higher pressure to the set of air springs at lowerpressure, thereby reaching an equilibrium state.

FIG. 2 schematically illustrates a leveling valve 50 according to oneconfiguration of the present invention. The leveling valve 50 includes ahousing 60 and a control arm 70. The housing 60 includes a supply port61 connected to the supply tank, an exhaust port 62 connected to theatmosphere, an air spring port 63 connected to the air springs on onerespective side of the vehicle, and a cross-flow port 64 connected to asecond leveling valve on another side of the vehicle. While FIG. 2illustrates the housing 60 having one air spring port, the housing 60may include two or more air spring ports to communicate with multiplesets of air springs disposed on a respective side of the vehicle.Further, the relative positioning of the ports with respect to eachother and with respect to the control arm may be varied and is notintended to be limited to the configuration illustrated in FIG. 2.

As shown in FIG. 2, the control arm 70 is connected to the housing 60and pivots about the housing 60 between a plurality of positions inresponse to compression and extension of the air springs disposed on oneside of the vehicle. When the air springs compress, the control arm 70pivots upward from a horizontal position to a first position, whichestablishes communication between the supply port 61 and the air springport 63 of the housing. Consequently, air is supplied from the supplytank to the respective air springs, thereby increasing the air pressureof the air springs. When the respective air springs extend, the controlarm 70 pivots downward from a horizontal position to a second position,which establishes communication between the exhaust port 62 and the airspring port 63 of the housing 60. Accordingly, air is removed from theair springs and released to the atmosphere, thereby decreasing the airpressure of the air springs. When the control arm 70 pivots away fromthe neutral position in either direction, the air spring port 63 doesnot communicate with the cross-flow port 64. At the neutral position,the control arm 70 is substantially oriented in a horizontal positionsuch that the control arm 70 extends parallel to the ground surface.When the control arm 70 is set in the neutral position, the air springport 63 communicates neither with the supply port 61 nor the exhaustport 62. The air spring port 63, instead, communicates with thecross-flow port 64 when the control arm 70 is set in the neutralposition so that the leveling valve 50 may communicate with anotherleveling valve disposed on an opposite side of the vehicle (as shown inFIG. 1A-C).

According to one exemplary configuration, the leveling valve may includea rotary member (not shown), such as a disk, received in a central bore(not shown) of the housing, in which the central bore is pneumaticallyconnected to each port of the housing. The rotary member is rotatablyconnected to the control arm so that pivoting movement of the controlarm induces rotation of the rotary member. The rotary member may rotatebetween a plurality of positions to alter communication between theports of the housing. Each leveling valve is a symmetrically dynamicequalized volume and pressure distributing valve having at least onerotary member (not shown) having different sized grooves or throughholes so as to deliver or purge air to the air springs when actuated ina response position, or to cut off air flow to the purge and supplyports when actuated in a neutral position and to open pneumaticcommunication at the cross-flow port in the neutral position.Accordingly, if a leveling valve on one side of the vehicle is in aneutral position, but the leveling valve on the opposite side of thevehicle is not in a neutral position, then there is no pneumaticcommunication between the two leveling valves. Only once both levelingvalves are actuated to the neutral position is pneumatic communicationbetween the pneumatic circuits on the opposite sides of the vehicleestablished.

Establishing cross-flow when neither leveling valve is independentlyadjusting the height of a respective side of vehicle mitigates theimbalanced pressure differentials between the air springs on each sideof the vehicle. It has been discovered that one factor contributing tothese pressure differentials is gravity. For example, when a vehicle isnegotiating a turn and experiences a dynamic lateral weight shift, oneof the leveling valves responds by supplying air to the compressed airsprings, whereas the other one of the leveling valves removes air fromthe extended air springs. However, the leveling valve that supplies airin response to the lateral weight shift tends to supply air with muchgreater force to overcome the force of gravity acting against thecompressed air springs. As a result, the leveling valve often suppliesmore air to its set of air springs than the volume of air removed fromthe other set of air springs on the opposite of the vehicle. Although apressure differential remains between the air springs on opposite sidesof the vehicle, the control arms return to a horizontal, neutralposition, in which the supply and purge ports of each leveling valve areclosed (e.g., within dead band position), thereby not accounting for theovercompensated air supplied to one of the sets of air springs.

The air management system of the present invention provides theunexpected advantage of mitigating the pressure differential between theair springs on each side of the vehicle by linking at least twoindependent pneumatic circuits to form one common pneumatic circuit whenboth leveling valves are in a neutral mode. In the present context, aleveling valve is in a “neutral mode” when the leveling valve is neithersupplying air from an air supply tank nor purging air into theatmosphere. Accordingly, the air management system of the presentinvention may adjust each side of the vehicle independently bypreventing communication between the first and second pneumatic circuitswhen at least one of the leveling valves is not in a neutral mode. Theair management system of the present invention may also link the firstand second pneumatic circuits into one common circuit by establishingcross-flow communication between the first and second pneumatic circuitsonly when both leveling valves are in a neutral mode. Establishingcross-flow between the air springs on each side of the vehicle allowsthe overcompensated air springs having greater pressure to release airto the air springs on the other side of the vehicle via the cross-flowline, thereby promoting equilibrium between air springs on both sides ofthe vehicle. Ultimately, the ability to selectively provide cross-flowwhen all the leveling valves are set in a neutral mode allows the airmanagement system to maintain a highly stable, safer and morecomfortable vehicle ride with better traction.

FIGS. 3 and 4 show different views of a mechanical-actuated valveaccording to one configuration of the present invention. The levelingvalve 300 shown in FIGS. 3 and 4 includes a valve body 310 comprising anupper housing 320 mounted to a lower housing 330, wherein a control arm340 is attached to a shaft extending through the upper housing 320. Theupper housing 320 is mounted to the lower housing 330 by fasteners (notshown) that are received in mounting holes that extend through cornersof the upper housing 320 and the lower housing 330.

Referring to FIGS. 4 and 5, the lower housing 330 comprises at leastfive ports 334 a-e, including a supply port 334 a, which connects to anair tank (not shown), an exhaust port 334 b for purging air from the airsprings (not shown), a first port 334 c that connects to a first set ofair springs (not shown), a second port 334 d that connects to a secondset of air springs (not shown), and a cross-flow port 334 e thatconnects to another leveling valve (not shown). The first and secondports 334 c and 334 d are arranged so that first spring port 334 c onone side of the lower housing 330 coincides with a second spring port334 d on the other side of the lower housing 330. The ports 334 a-d arefurther arranged so that supply port 334 a on one side of the lowerhousing 330 coincides with the exhaust port 334 b on an opposite side oflower housing 330.

The lower housing 330 includes separate airflow passages (not shown) toeach port 334 a-e of the lower housing 330, so that air supplied fromthe supply port 334 a or air purged to the exhaust port 334 b occursindependently from air flowing through the cross-flow port 334 e.Referring to FIG. 5, the lower housing 330 includes a first surface 336defining a plurality of circular-shaped cavities 338 a-c. The supplyport 334 a is linked to a supply cavity 338 a by one airflow passageformed in the lower housing 330, and the exhaust port 334 b is linked toan exhaust cavity 338 b by a second airflow passed formed in the lowerhousing 330. The cross-flow port 334 e is linked to a cross-flow cavity338 c by a third air flow passage formed in the lower housing 330. Thefirst and second spring ports 334 c, 334 d may be linked by a reservoircavity (not shown) formed in the lowered housing 330.

FIGS. 4 and 6A-C show a rotary disk 350 according to one configurationof the present invention. Referring to FIG. 4, the rotary disk 350 isreceived in a central bore defined between the lower and upper housing.The rotary disk 350 includes a central aperture 352 configured torotatably receive a post (not shown), which extends from the lowerhousing 330 and through the upper housing 320 to connect to the controlarm. The rotary disk 350 is configured to rotate about the post (notshown) within a central bore of the lower housing 330, thereby definingthe central aperture 352 as a pivot point. The rotary disk 350 includestwo oblong-shaped slots 354 spaced around the central aperture 352 withdisk surface 353 defined therebetween and along the periphery of therotary disk 350. The disk surface 353 corresponds to regions of therotary disk 350 that only includes the solid surface of the rotary disk350, not any void spaces defined by the slots. Accordingly, when thedisk surface 353 of the rotary disk 350 completely overlaps a respectivecavity, air flow is restricted from entering through the respectivecavity. The rotary disk 350 further includes a cross-flow slot 355,which is smaller than both the oblong-shaped slots 354.

The angular position of the rotary disk 350 changes as the control arm340 pivots about the valve body 310 of the valve 300. As shown in FIG.6A, when the control arm 340 is set to a horizontal position, the rotarydisk 350 is set to a neutral position, in which the disk surface 353 ofthe rotary disk 350 overlies both the supply cavity 338 a and theexhaust cavity 338 b of the lower housing 330. Thus, at the neutralposition, the rotary disk 350 is set within the dead band range ofrotation. Consequently, when the rotary disk 350 is set at the neutralposition, the air springs are connected to neither the supply port 334 anor the exhaust port 334 b. However, the cross-flow slot 355 overliesthe cross-flow cavity so that the first and second springs are incommunication with the cross-flow port 334 e. As shown in FIG. 6B, dueto clockwise rotation of the control arm 340, the rotary disk 350rotates to an angular position in which the arrangement of slots 354,355 connects the supply cavity 338 a with the reservoir cavity (notshown) so that the air springs receive air from the supply tank, therebyincreasing the air pressure of the air springs. As shown in FIG. 6C, dueto counterclockwise rotation of the control arm 340, the rotary disk 350rotates to an angular position in which the arrangement of slots 354,355 connects the exhaust cavity 338 b with the reservoir cavity (notshown) so that air is removed from the air springs into the atmosphere.In other configurations, one condition for clockwise movement of onerotary disk 350 may correspond to counterclockwise rotation of anotherrotary disk 350 according to the present invention. For example,clockwise rotation of the rotary arm may induce the rotary disk 350 torotate to an angular position in which the arrangement of slots 354, 355connects the exhaust cavity 338 b with the spring reservoir cavity (notshown) so that the air springs purge air into the atmosphere, therebydecreasing the air pressure of the air springs. Furthermore,counterclockwise rotation of the rotary arm may induce the rotary diskto rotate to an angular position in which the arrangement of slots 354,355 connects the supply cavity 338 a with the spring reservoir cavity(not shown) so that air is supplied from the supply tank to the airsprings.

FIGS. 10, 11, and 12A-C illustrate a lower housing 430 according oneconfiguration of the present invention. The lower housing 430 isconfigured to mount to the upper housing 320 shown in FIGS. 3 and 4 toform a valve body of a leveling valve. Similar to the configurationshown in FIGS. 3-5, the lower housing 430 comprises at least five ports434 a-e, including a supply port 434 a that connects to an air tank (notshown), an exhaust port 434 b for purging air from the air springs (notshown), a first port 434 c that connects to a first set of air springs(not shown), a second port 434 d that connects to a second set of airsprings (not shown), and a cross-flow port 434 e that connects toanother leveling valve (not shown). The lower housing 430 can optionallyfurther include a sixth port 434 f (shown in FIGS. 12A and 12B) thatconnects to a dump valve (not shown), wherein the dump valve isconfigured to remove all of the air from each air spring of the airmanagement system simultaneously.

As shown in FIGS. 12A-C, the lower housing 430 includes separate airflowpassages to each port 434 a-f, including a supply passage 432 aconnected to the supply port 434 a, an exhaust passage 432 b connectedto the exhaust port 434 b, a first passage 432 c connected to the firstport 434 c, a second passage 432 d connected to the second port 434 d, across-flow passage 432 e connected to the cross-flow port 434 e, and adump passage 432 f connected to the dump port 434 f. The lower housing430 includes a first surface 436 defining a plurality of circular-shapedblind holes 438 a-c and a reservoir cavity 439. The blind holes 438 a-cinclude a supply hole 438 a linked to the supply port 434 a by thesupply passage 432 a, an exhaust hole 438 b linked to the exhaust port434 b by the exhaust passage 432 b, and a cross-flow hole 438 c linkedto the cross-flow port 434 e by the cross-flow passage 432 e. The lowerhousing 430 further includes a central hole 438 d configured to receivea post (not shown) that extends through the upper housing 320 to receivethe control arm. The first passage 432 c, the second passage 432 d, andthe dump passage 432 f are interconnected together and extend from thereservoir cavity 439. In one example shown in FIG. 10, the lower housing430 may include an elevated surface 437 protruded from the first surface436, in which the holes 438 a-c and cavity 439 are defined along theelevated surface 437. The elevated surface 437 of the lower housing 430is configured to engage a lower surface of the upper housing 320 todefine a chamber therein.

FIG. 13 illustrates a rotary disk 450 according to a configuration ofthe present invention. Similar to the configuration shown in FIGS. 4 and6A-C, the rotary disk 450 includes a central aperture 452, twooblong-shaped slots 454, and a cross-flow slot 455 with disk surface 453extending therebetween and along the periphery of the rotary disk 450.The central aperture 452 is disposed between the two oblong-shaped slots454 and the cross-flow slot 455. The two oblong-shaped slots 454 aresymmetrically spaced from a central axis A-A of the rotary disk 455, andthe cross-flow slot 455 overlies the central axis A-A of the rotary disk450, in which the central aperture 452 is disposed between theoblong-shaped slots 454 and the cross-flow slot 455. The cross-sectionalarea of the cross-flow slot 455 is substantially smaller than thecross-sectional area of each oblong-shaped slot 454. For example, thecross-sectional area of the cross-flow slot 455 is at least three, four,five, ten, twenty, thirty, forty or more times smaller than thecross-sectional area of the oblong-shaped slots 454. In somenon-limiting embodiments (e.g., FIGS. 33-36), the width or diameter ofthe cross-flow slot 455 may vary across its depth thereof such that thewidth or diameter of the cross-flow slot 455 has a first transversedimension at a first face of the rotary disk 450 and a second transversedimension at a second face of the rotary disk 450, in which the firsttransverse dimension is greater than the second transverse dimension.

The rotary disk 450 is received on the elevated surface 437 of the lowerhousing 430, and the central aperture 452 receives a shaft (not shown)extending from the first surface 436 of the lower housing 430 to theupper housing (not shown) of the rotary valve. Similar to theconfiguration shown in FIGS. 4 and 6A-C, the rotary disk 450 isconfigured to rotate about the shaft between a plurality of positionsincluding a neutral position, a first angular position, and a secondangular position. At the neutral position, the disk surface 453 of therotary disk 450 overlies both the supply hole 438 a and the exhaust hole438 b of the lower housing 430 such that the air springs are connectedto neither the supply port 434 a nor the exhaust port 434 b. Thus, therotary disk 450 is set within the dead band range of rotation when setat a neutral position. At the neutral position, the cross-flow slot 455overlies the cross-flow hole 438 c so that the first and second springsare in communication with the cross-flow port 434 e.

When the rotary disk 450 is rotated away from the neutral position in aclockwise direction to the first angular position, the oblong-shapedslots 454 connect the supply hole 438 a with the reservoir cavity 439 sothat the air springs receive air from the supply tank, therebyincreasing the air pressure of the air springs. When the rotary disk 450is set at the first angular position, the cross-flow slot 455 is rotatedaway from the cross-flow hole 438, such that the dead band 453 overliesthe cross-flow hole 438 c. When the rotary disk 450 is rotated away fromthe neutral position in a counter-clockwise direction to the secondangular position, the oblong-shaped slots 454 connect the exhaust hole438 b with the reservoir cavity 439 so that air is removed from the airsprings. When the rotary disk 450 is set at the second angular position,the cross-flow slot 455 is rotated away from the cross-flow hole 438 c,such that dead band 453 overlies the cross-flow hole 438 c.

Due to the sizing of the cross-flow slot 455, the rotary disk 450 onlyneeds to be slightly rotated about 1° to 2° in either the clockwise orthe counter-clockwise direction from the neutral position for the deadband 453 to completely overlie the cross-flow hole 438 c. Thus, therotary disk may transition quickly from allowing cross-flow between thefirst and second pneumatic circuits to controlling the air flow to oneside of the vehicle independently without cross-flow taking place. Whilethe rotary disk is rotating about 1° to 2° in either the clockwise orthe counter-clockwise direction from the neutral position, theoblong-shaped slots 454 are neither in communication with the supplyhole 438 a nor the exhaust hole 438 b of the lower housing 430. When therotation speed of the rotary disk exceeds a predetermined thresholdspeed, the rotary disk 450 may rotate from the first angular position tothe second angular position without allowing air to flow through thecross-flow hole 438 c and the cross-flow port 434 e during thetransition. Accordingly, when the vehicle experiences subsequent dynamicweight shifts, the rotary disk may switch between supplying and removingair to and from the air springs without allowing cross-flow to takeplace between the first and second pneumatic circuits during thetransition.

FIGS. 14A and 14B illustrate a first poppet 460 according to oneconfiguration used in the present invention. The first poppet 460includes a cylindrical-shaped body 462 extending from a first end 464 toa second end 466. The first poppet 460 includes a passage 463 extendingthrough the body 462 from an first opening 463 a defined along the firstend 464 to a second opening 463 b defined along the second end 466. Thesize of the first opening 463 a is equivalent to the size of the secondopening 463 b. The first poppet 460 is disposed in both the supply hole438 a and the exhaust hole 438 b of the lower housing 430, in which thefirst end 464 projects out of the first surface 436 of the lower housing430 and engages the rotary disk 450 to provide an air tight seal betweenthe supply and exhaust holes 438 a, 438 b and the oblong-shaped slots454. In some other configurations (not shown), the size of the firstopening 463 a may be different than the size of the second opening 463 bsuch that the diameter or width of the passage 463 varies through itslength thereof. In one example, the first opening 463 a may comprise afirst diameter, and the second opening 463 b may comprise a seconddiameter, in which the second diameter is less than the first diameter.

FIGS. 15A and 15B illustrate a second poppet 470 according to oneconfiguration of the present invention. Similar to the first poppet 460,the second poppet 470 includes a cylindrical-shaped body 472 extendingfrom a first end 474 to a second end 476. The first poppet 470 includesa passage 473 extending through the body 472 from an first opening 473 adefined along the first end 474 to a second opening 473 b defined alongthe send end 476. Unlike the first poppet 460, the size of the firstopening 473 a in the second poppet 470 is smaller than the size of thesecond opening 473 b. The size and shape of the first opening 473 a ofthe second poppet 470 corresponds to the size and shape of thecross-flow slot 455 in the rotary disk 450. The second poppet 470 isdisposed in the cross-flow hole 438 c of the lower housing, in which thefirst end 474 projects of the first surface 436 of the lower housing 436and engages the rotary disk 450 to provide an air tight seal between thecross-flow slot 455 of the rotary disk 450 and the cross-flow hole 438c.

In one non-limiting embodiment, the lower housing 430 may comprise afourth blind hole (not shown) disposed along the first surface 436,whereby the fourth blind hole is aligned with the cross-flow hole 438 cand the reservoir cavity 439 is disposed between the fourth blind holeand the cross-flow hole 438 c. In some embodiments, the fourth blindhole is ninety degrees separated from the supply and exhaust holes 438a, 438 b with respect to the central hole 438 d and one-hundred-eightydegrees separated from the cross-flow hole 438 c with respect to thecentral hole 438 d. The fourth blind hole is not in pneumaticcommunication with any one of the supply passage 432 a, exhaust passage432 b, first passage 432 c, second passage 432 d, cross-flow passage 432e, and the dump passage 432 f. In some embodiments, a third poppet (notshown) may be disposed in the fourth blind hole. In some embodiments,the third poppet may comprise the same configuration as the first poppet460 received in the cross-flow hole 438 c such that the third poppetcomprises a first end configured to project above the first surface 436of the lower housing 430. When the rotary disk 450 is received on thefirst surface 436 of the lower housing 430, the third poppet isconfigured to engage the rotary disk 450 such that a bottom surface ofthe rotary disk 450 engages four poppets: the pair of first poppets 460received in the supply and exhaust holes 438 a, 438 b, the second poppet470 received in the cross-flow hole, and the third poppet received inthe fourth blind hole. By engaging the four poppets that are displacedfrom each ninety degrees with respect to the center hole 438 d, therotary disk 450 is maintained at a level position.

FIG. 43 illustrates the relationship between the angle of the controlarm and the air pressure at the various ports of the lower housing of aleveling valve in an exemplary embodiment according to the presentinvention. As shown in FIG. 43, the x-axis reflects the time ofmotorized operation in seconds, and the y-axis indicates both the angleof the control arm in degrees (i.e., represented by the solid line) andthe air pressure in pressure-per-square-inch-gauge (PSIG) of the variousvalve ports in response to the changing control arm angle (representedby the dotted or dashed lines). Referring to FIG. 43, as the vehicledynamically encounters a changing road condition, i.e., when the controlarm pivots initially away from the neutral position, indicated by thex-axis, the air pressure at the working port (i.e., spring portconnected to the air spring) increases exponentially, while the airpressure at the supply port slightly dips. Accordingly, the levelingvalve is configured to respond quickly at supplying air pressure to theair spring when the control arm pivots away from the neutral position toa supply position. Then, as the control arm initially pivots back towardthe neutral position, as indicated at about 14 seconds on the x-axis inFIG. 43, the air pressure at the spring port levels is maintained at aconstant level. Once the leveling arm returns back to the neutralposition, as indicated at about 28 seconds on the x-axis in FIG. 43, theair pressure at the cross-flow port spikes to about 90 PSIG and the airpressure at the spring port decreases slightly. As a result, thepressure in the connected air spring decreases slightly so that airsprings disposed on opposite sides of the vehicle become equal. Then, asthe vehicle continues driving and encounters a different changing roadcondition, i.e., as the control arm rotates away from the neutralposition in the opposite direction, starting about 29 seconds on thex-axis in FIG. 43, the air pressure at the exhaust port increases suchthat the air pressure at the spring port decreases exponentially, at afaster rate, compared to the decrease of air pressure when the controlarm is set in the neutral position. Accordingly, the air pressure in theconnected air spring reduces significantly in response to the controlarm switching to an exhaust position. Thus, FIG. 43 demonstrates thatthe leveling valve according to the present invention operates accordingto three unique stages: (i) a supply mode, (ii) an exhaust mode, and(iii) a cross-flow mode. In addition, FIG. 43 demonstrates that there isno bleed over between the separate stages such that the leveling valvemay operate in only one of the three modes at a single time.

According to various embodiments, FIG. 44 illustrates a method 900 foradjusting air pressure of an air management system 100 comprising one ormore air supply tanks 32, 33, a first pneumatic circuit disposed on afirst side of a vehicle, and a second pneumatic circuit disposed on asecond side of the vehicle. As shown in FIG. 44, the method 900comprises a step 910 of adjusting independently the air pressure of thefirst pneumatic circuit by a first leveling valve 16. In variousembodiments, adjusting independently the air pressure of the firstpneumatic circuit includes either supplying air from the one or more airsupply tanks 32, 33 to the first pneumatic circuit or removing air fromthe first pneumatic circuit to the atmosphere. As shown in FIG. 44, themethod 900 comprises a step 920 of adjusting independently the airpressure of the second pneumatic circuit by a second leveling valve 17.In various embodiments, adjusting independently the air pressure of thesecond pneumatic circuit includes either supplying air from the one ormore air supply tanks 32, 33 to the second pneumatic circuit or removingair from the second pneumatic circuit to the atmosphere. As shown inFIG. 44, the method 900 comprises a step 930 of establishing pneumaticcommunication between the first pneumatic circuit and the secondpneumatic circuit only when both the first leveling 16 and the secondleveling valve 17 are set in a neutral mode. In various embodiments, theleveling valve in the neutral mode is neither supplying air from the oneor more air supply tanks or removing air into the atmosphere.

The air management system may include mechanically- orelectronically-actuated leveling valves to control communication betweenthe first and second pneumatic circuits. In one exemplary configuration,the air management system may include a leveling valve disposed at eachair spring, in which each leveling valve includes a manifold and aplunger disposed in a chamber of the manifold. The plunger is configuredto move in the chamber of the manifold between one or more positionsincluding at least a first position to establish cross-flow between thefirst and second pneumatic circuits and a second position to adjustindependently the height of a respective side of the vehicle. Ratherthan having a control arm to actuate air flow, the manifold may includean electronic actuator to move the plunger between the one or morepositions so that air flow may be supplied or removed from therespective air spring. In one exemplary configuration, the airmanagement system may have a central manifold that includes individualports connected to each air spring of the air management system.

In one exemplary configuration, the leveling valves may consist of oneor more solenoid valves that allow air to be adjusted to each side ofthe vehicle independently while selectively allowing cross-flow betweenthe first and second pneumatic circuits to equalize air pressure betweenthe first and second sets of air springs. The air management system mayfurther include a controller in electrical communication (e.g. wirelessor wired) with the leveling valves to control the operation of theelectronically-actuated leveling valves. The air management system mayfurther include air pressure sensors provided in the air lines to sensepressure changes and imbalances and communicate such data to acontroller in electrical communication (e.g. wireless or wired) with theleveling valves or to one or more leveling valves themselves. The airmanagement system may further include inputs based on ride heightsensors for height control, flow sensors at one or more of the ports,and communication with electronic systems, e.g., any electronicstability control (ESC), including, but not limited to electronicstability program (ESP), dynamic stability control (DSC), vehiclestability control (VSC), automatic traction control (ATC), and/or rollstability control systems of the vehicle 1. Linking actuation of the airmanagement system to a controller that also linked to the ESP, DSC ATC,or VSC of the vehicle enhances the overall safety of the vehicle bysyncing braking and steering control with the operation of the airmanagement system.

In various configurations, the controller of the air management systemis in electrical communication with the leveling valves, sensors, andother vehicle electronic systems (e.g., ESC, ESP, DSC, VSC, ATC, etc).In various embodiments, the controller may receive measurement signals,such as height and pressure measurements of the air springs, transmittedfrom the sensors. Based on the measurement and data signals, thecontroller is configured to calculate a current state of each air springof the air management system and a dynamic operating state of thevehicle. In one configuration, the controller is configured to calculatea pressure differential or a height differential between the air springsof the air management system based on the received measurement and datasignals. The controller is configured to actuate the valve in the activemode when the pressure differential or the height differential betweenthe air springs is above a predetermined threshold and actuate the valvein a neutral mode when the pressure differential or height differentialis below a predetermined threshold. Accordingly, when there is asubstantial height difference between respective sides of the vehicle,the controller is configured to transmit commands to the leveling valvesto independently adjust the height of the air springs of its respectivepneumatic circuit to bring the vehicle to a level condition at a fasterrate. In various embodiments, the controller may transmit commands tothe leveling valve to operate in an active mode at any vehicle speed.When there is only a slight height differential between the respectivesides of the vehicle that does not trigger a rolling condition, thecontroller is configured to transmit a command to the leveling valves tobe set in the neutral mode and mitigate any pressure differentialbetween the air springs by establishing cross-flow between the airsprings. In various embodiments, the controller transmit commands to theleveling valves to operate in the neutral mode at any vehicle speed,including speeds substantially above zero miles-per-hour orkilometers-per-hour.

FIGS. 7-9 illustrate air managements systems comprising a series of airlines, in which the lengths of all the airlines extending between arespective air spring and a control valve have an equal length andinternal diameter. FIG. 7 illustrates an air management system 200 acomprising a first pneumatic circuit, a second pneumatic circuit, and atleast two leveling valves 300 a. Each pneumatic circuit includes one ormore air springs 205 a, an air supply tank 210 a, a supply line 220 aextending between the leveling valve 300 a and the supply tank 210 a,and a set of spring lines 230 a connecting the one or more air springs205 a to the leveling valve 300 a. The air management system 200 afurther includes a pressure protection valve 240 a (not required for allair management systems) connected to each supply line 220 a. In someconfigurations of the air management system 200 a, the spring lines 230a may have equal lengths and diameters, and the supply lines 220 a mayhave equal lengths and diameters. Each leveling valve 300 a ismechanically actuated by a control arm 305 and configured toindependently adjust the air flow to one of the first or secondpneumatic circuits. The leveling valves 300 a are linked together by across-flow line 250 a to establish fluid communication between the firstand second pneumatic circuits when all leveling valves are set in theneutral mode. Thus, the leveling valves 300 a are configured to providecross-flow between first and second pneumatic circuits when neither airis supplied from the air tank to the air springs nor air is removed fromthe air springs to the atmosphere.

FIG. 8 illustrates an air management system 200 b comprising a firstpneumatic circuit, a second pneumatic circuit, and at least two levelingvalves 300 b. Each pneumatic circuit includes one or more air springs205 b, an air supply tank 210 b, a supply line 220 b extending betweenthe leveling valve 300 b and the supply tank 210 b, and a set of springlines 230 b connecting the one or more air springs 205 b to the levelingvalve 300 b. In some configurations of the air management system 200 b,the spring lines 230 b may have equal lengths and diameters, and thesupply lines 220 b may have equal lengths and diameters. The airmanagement system 200 b further includes a pressure protection valve 240b connected to each supply line 220 b. As shown in FIG. 8, the levelingvalves 300 b are electronically-actuated leveling valves connectedtogether by a cross-flow line 250 b. The electronically-actuatedleveling valve is configured to provide cross-flow between first andsecond pneumatic circuits when neither air is supplied from the air tankto the air springs nor air is removed from the air springs to theatmosphere, i.e., in the neutral mode.

FIG. 9 illustrates an air management system 200 c comprising a firstpneumatic circuit, a second pneumatic circuit, and at least two levelingvalves 300 c. The air management system 200 c comprises one or more airsprings 205 c, a supply air tank 210 c that is connected to eachleveling valve 300 c by a respective supply line 220 c, in which apressure protection valve 240 c is incorporated into the supply line 220c. Each leveling valve 300 c is connected to the one or more air springs205 c by a series of spring lines 230 c. In some configurations of theair management system 200 c, the spring lines 230 c may have equallengths and diameters, and the supply lines 220 c may have equal lengthsand diameters. The leveling valves 300 c are connected together by across-flow line 250 c. As shown in FIG. 9, the leveling valves 300 c areelectronically-actuated leveling valves and are in electricalcommunication with a control unit 260. The electrical communication maybe established by a wired connection or a wireless connection. Theelectronically-actuated leveling valve is configured to providecross-flow between first and second pneumatic circuits when neither airis supplied from the air tank to the air springs nor air is removed fromthe air springs to the atmosphere, i.e., in the neutral mode.

FIGS. 16-18 illustrate air management systems that sync control of airflow with an electronic control unit. FIG. 16 shows an air managementsystem 500 a comprising a first pneumatic circuit 510 a, a secondpneumatic circuit 520 a, and at least two leveling valves 600 a. Eachpneumatic circuit 510 a, 520 a, includes one or more air springs 530 a.Each leveling valve 600 a is configured to independently adjust the airflow to one of the first or second pneumatic circuits. The levelingvalves 600 a are linked together by a cross-flow line 550 a to establishfluid communication between the first and second pneumatic circuits 510a, 520 a when all leveling valves 600 a are set in the neutral mode.Each leveling valve 600 a is mechanically actuated by a control arm 610and includes a control arm sensor (not shown) disposed in the housing ofthe leveling valve 600 a to detect the position of the control arm. Inone example, the control arm sensor may be a potentiometer. The controlarm sensor is in electrical communication with a control unit 650 a,which may be integrated into ESP, DSC or VSC of the vehicle. Theelectrical communication may be established by a wired connection or awireless connection. The control arm sensor is configured to detect theposition of the control arm and transmit the position of the control armto the control unit 650 a as a control arm position input. The controlunit 650 a is configured to determine vehicle height at each respectiveside of the vehicle based on the control arm position input.

FIG. 17 shows an air management system 500 b comprising an air supplytank 505 b, a first pneumatic circuit 510 b connected to the supply tank505 b, a second pneumatic circuit 520 b connected to the supply tank 505b, and at least two leveling valves 600 b, in which each leveling valveis configured to control independently the air flow to one of the firstor second pneumatic circuits 510 b, 520 b. In other configurations ofthe air management system 500 b, the air management system may have morethan one air supply tank 505 b. Each pneumatic circuit 510 b, 520 b,includes one or more air springs 530 b. Each leveling valve 600 bincludes a valve element (not shown) configured to move between aplurality of positions including a neutral position, a supply position,and an exhaust position. In one example, the valve element may be apoppet, a plunger, etc. When the valve element is set in the neutralposition, the port neither supplies air to the air springs from the airtank nor removes air from the air springs to the atmosphere. Eachleveling valve 600 b is electronically actuated by an electronicactuator 620. In one example, the electronic actuator 620 may be asolenoid, a motor, etc. As shown in FIG. 17, the leveling valves 600 bare connected together by a cross-flow line 550 b to establish fluidcommunication between the first and second pneumatic circuits 510 b, 520b when all valve elements are set in the neutral position. The airmanagement system further includes a plurality of leveling sensors 630,including at least one leveling sensor 630 disposed at each side of thevehicle to detect vehicle height positions, air pressure of a respectiveair spring, or any other information pertinent to vehicle stability. Thelevel sensors 630 are in electrical communication with a control unit650 b. The electrical communication may be established by a wiredconnection or a wireless connection. Each leveling sensor 630 isconfigured to transmit measurements to the control unit 650 b as avehicle leveling input. The control unit 650 b is configured todetermine vehicle height at each respective side of the vehicle based onthe vehicle leveling input. The control unit 650 b is further configuredto control the electronic actuators 620 at each leveling valve 600 b totrigger movement of the valve element to a desired position, therebycontrolling the air flow to the first and second pneumatic circuits.

In one configuration, the control unit 650 b is configured to actuatethe leveling valves 600 b to establish cross-flow when the pressuredifferential or height differential between the air springs of the firstand second pneumatic circuits 510 b, 520 b are within a predeterminedthreshold. The control unit 650 is configured to actuate the valves 600b in the active mode to independently adjust the air pressure of itsassociated pneumatic circuit when the pressure differential or heightdifferential between the air springs of the first and second pneumaticcircuits 510 b, 520 b are greater than a predetermined threshold. Thecontrol unit 650 b may determine the pressure or height differential ofthe air springs 530 b based on measurement signals received from thesensors 630.

FIG. 18 shows an air management system comprising an air supply tank 505c, a first pneumatic circuit 510 c, a second pneumatic circuit 520 c,and a manifold 600 c that, in certain embodiments, is disposed at ornear the center of the vehicle. In other configurations of the airmanagement system 500 c, the air management system may have more thanone air supply tank 505 c. The manifold 600 c is connected to the supplytank 505 c by one or more supply lines 506 c. Each pneumatic circuit 510c, 520 c, includes one or more air springs 530 c. The manifold 600 cincludes a plurality of ports 640, including at least one port 640connected to each air spring 530 c by a spring line 535 c. The manifold600 c includes a valve element (not shown) disposed at each port 640 tocontrol the flow of air through the port. In one example, the valveelement may be a poppet, a plunger, etc. The valve element is configuredto move between a plurality of positions including a neutral position, asupply position, and an exhaust position. When the valve element is setin the neutral position, the port neither supplies air to the airsprings from the air tank nor removes air from the air springs to theatmosphere. The manifold 600 c further includes a cross-flow passage(not shown) to establish fluid communication between the first andsecond pneumatic circuits 510 c, 520 c when all the valve elements areset in the neutral position. The manifold 600 c further includes anelectronic actuator (not shown) disposed at each port to triggermovement of the valve element. In one example, the electronic actuatormay be a solenoid, a motor, etc. The air management system 500 c furtherincludes a plurality of leveling sensors 630, including at least oneleveling sensor 630 disposed at each side of the vehicle to detectvehicle height positions, air pressure of a respective air spring, orany other information pertinent to vehicle stability. The level sensors630 are in electrical communication with a control unit 650 c. Theelectrical communication may be established by a wired connection or awireless connection. Each leveling sensor 630 is configured to transmitmeasurements to the control unit 650 c as a vehicle leveling input. Thecontrol unit 650 c is configured to determine vehicle height at eachrespective side of the vehicle based on the vehicle leveling input. Thecontrol unit 650 c is further configured to control the electronicactuators at each port 640 to trigger the movement of the valve elementto a desired position, thereby controlling the air flow to the first andsecond pneumatic circuits 510 c, 520 c.

In one configuration, the control unit 650 c is configured to actuatethe manifold 600 c to establish cross-flow when the pressuredifferential or height differential between the air springs of the firstand second pneumatic circuits 510 c, 520 c are within a predeterminedthreshold. The control unit 650 c is configured to actuate the manifold600 c in the active mode to independently adjust the air pressure of itsassociated pneumatic circuit when the pressure differential or heightdifferential between the air springs of the first and second pneumaticcircuits 510 c, 520 c are greater than a predetermined threshold. Thecontrol unit 650 c may determine the pressure or height differential ofthe air springs 530 b based on measurement signals received from thesensors 630.

FIGS. 19 and 20 illustrate air management systems that sync control ofair flow with a control unit associated with each air spring. FIG. 19shows an air management system 700 a comprising an air source 702 a, asupply air tank 704 a, a first pneumatic circuit 710 a disposed on afirst side of the vehicle, and a second pneumatic circuit 720 a disposedon a second side of the vehicle. Each pneumatic circuit 710 a, 720 a,includes one or more air springs 730 a. Each air spring 730 a comprisesa control unit 740 a disposed within a chamber of the air spring 730 a.The control unit 740 a comprises a housing 780 a mounted to a top plate732 a of the air spring 730 a. By being disposed within the air spring730, the control unit 740 a is not exposed to the outside environment,thereby being protected from damage caused by debris or inclementweather conditions. The control unit 740 a is configured to adjust theheight of the air spring 730 b to a desired height that is determinedbased on one or more operating conditions monitored by the control unit740 a. The control unit 740 a may take into account conditions of otherair springs 730 a of the air management system 700 a in determining thedesired height for its associated air spring 730 a, but the control unit740 a adjusts the height of its associated air spring 730 a independentto the other control units 740 a of the air management system 700 a. Asshown in FIG. 19, a cross-flow line 760 a connects the control unit 740a of an air spring 730 a in the first pneumatic circuit 710 a to acontrol unit 740 a of an air spring 730 a in the second pneumaticcircuit 720 a. Each control unit 740 a is configured to providecross-flow between the two air springs 730 a of the first and secondpneumatic circuits 710 a, 720 a when neither air is supplied from theair source 702 a to the air springs 730 a nor air is removed from theair springs 730 a to the atmosphere, i.e., in the neutral mode.

Referring to FIGS. 19 and 22, the control unit 740 a comprises an inletport 741 a disposed along a first surface of the housing 780 a, anoutlet port 742 a disposed along the first surface of the housing 780 a,a cross-flow port 743 a disposed along a first surface of the housing780 a, and a delivery port 744 a disposed along a second surface of thehousing 780 a. The control unit 740 a comprises a valve chamber 745 aand a plurality of passages 751 a-754 a connecting the delivery port 744a, the inlet port 741 a, the outlet port 742 a, and the cross-flow port743 a to the valve chamber 745 a. The inlet port 741 a is configured toconnect to a fitting 736 a disposed on the top plate 732 a, therebyestablishing pneumatic communication between the air supply tank 704 aand the control unit 740 a. The outlet port 742 a is configured toconnect to an exhaust port 738 a disposed on the top plate 732 a,thereby establishing pneumatic communication between the atmosphere andthe control unit 740 a. The cross-flow port 743 a is configured toconnect to the cross-flow line 760 a, thereby establishing pneumaticcommunication between a control unit 740 a of a first air spring 730 aand a control unit 740 a of a second air spring 730 a. The delivery port744 a is configured to establish pneumatic communication between thevalve chamber 745 a and the chamber of the air spring 730 a such thatair may be supplied into or released from the chamber of the air spring730 a.

As shown in FIG. 22, the control unit 740 a comprises a valve 746 adisposed in the valve chamber 745 a for selectively controlling thesupply and exhaust of air to and from the chamber of the air spring 730a. The valve 746 a is configured to switch between a plurality of modes,including a first mode in which the air is released out of the chamberof the air spring 730 a, a second mode in which the air is supplied intothe chamber of the air spring 730 a, a neutral mode in which the chamberof the air spring 730 a is pneumatically connected to the cross-flowline 760 a. In the first mode, the valve 746 a establishes pneumaticcommunication between the inlet port 741 a and the delivery port 744 a.In the second mode, the valve 746 a establishes pneumatic communicationbetween the outlet port 742 a and the delivery port 744 a. When thevalve 746 a is set in the first or second modes, the valve 746 a isindependently adjusting the height of its associated air spring 730 a(i.e., active mode) such that the valve 746 a is not in pneumaticcommunication with other air springs 730 a of the air management system700 a. In the neutral mode, the valve 746 a establishes pneumaticcommunication between the cross-flow port 743 a and the delivery port744 a, resulting in cross-flow between its associated air spring 730 aand a second air spring 730 a disposed on an opposite side of thevehicle.

The valve 746 a may take any suitable form or configuration, such as atwo-way, three-way, or variable position valve, to selectively controlthe flow of air in and out of the chamber of the air spring 730 a at aplurality of flow rates. In one example (not shown), the valve 746 acomprises a rotary member disposed in the valve chamber and anelectronic actuator operatively linked to the rotary member. In oneconfiguration, the electronic actuator is a stepper motor. The rotarymember is configured to rotate between a plurality of positionsincluding a first position establishing pneumatic communication betweenthe inlet port and the delivery port, a second position establishingpneumatic communication between the outlet port and the delivery port,and a third position establishing pneumatic communication between thedelivery port and the cross-flow port. The electronic actuator (e.g.,stepper motor) is configured to receive energy from a power source andactuate movement of the rotary member between the plurality ofpositions. In some configurations, the rotary member is a diskcomprising a plurality of holes configured to selectively overlie theplurality of passages at the first, second, and third positions, and thestepper motor includes a shaft that is rotatably coupled to the disk. Insome configurations, the stepper motor is configured to actuate movementof the rotary member to a plurality of positions such that thevolumetric flow rate for supplying or removing air from the chamber mayvary at each respective position of the rotary member. Accordingly, thestepper motor may actuate movement of the rotary member to a firstposition, in which air is supplied or removed from the chamber of theair spring 730 a at a first rate, and the stepper motor may actuatemovement of the rotary member to a second position, in which air issupplied or removed from the chamber of the air spring 730 a at a secondrate that is greater or less than the first rate.

In another example (not shown), the valve 746 a may include a plungerreceived in the valve chamber 745 a and a solenoid operatively connectedto the plunger. The plunger is configured to slide within the valvechamber 745 a between a plurality of positions, including a firstposition establishing pneumatic communication between the inlet port andthe delivery port, a second position establishing pneumaticcommunication between the outlet port and the delivery port, and a thirdposition establishing pneumatic communication between the delivery portand the cross-flow port. The solenoid is configured to receive energyfrom a power source and actuate movement of the plunger between theplurality of positions. In some configurations, the solenoid isconfigured to actuate movement of the plunger to a plurality ofpositions such that the volumetric flow rate for supplying or removingair from the chamber may vary at each respective position of theplunger.

In another example as shown FIGS. 26A and 26B, the valve 746 a mayinclude a cylindrical-shaped manifold 780 and a throttle element 790telescopically received in the manifold 780 such that the throttleelement 790 is in sliding engagement with the interior surface of themanifold 780. In one configuration, the manifold 780 includes aplurality of openings 781-783 disposed along a surface of the manifold780. The plurality of openings 781-783 include a first opening 781disposed approximate a first end of the manifold 780, a second opening782 disposed approximate a second end of the manifold 780, a thirdopening 783 disposed between the first and second openings 781, 782. Thefirst opening 781 is configured to provide pneumatic communicationbetween the inlet port 741 a and the delivery port 744 a of the controlunit 740 a. The second opening 782 is configured to provide pneumaticcommunication between the chamber of the air spring and the outlet port742 a of the control unit 740 a. The third opening 783 is configured toprovide pneumatic communication between the cross-flow port 743 a andthe chamber of the air spring.

In one configuration, the throttle element 790 is configured to receivean electric signal and slide along the longitudinal axis of the manifold780 in response to receiving an electric signal. By sliding along thelongitudinal axis of the manifold 780, the throttle element 790 isconfigured to control the exposure of the first, second, and thirdopenings 781-783 such that the valve 746 a is configured to selectivelysupply air, remove air, or establish cross-flow for the associated airspring 730 a. The displacement of the throttle element 790 furthercontrols the rate of air flow through the control unit 740 a. Thethrottle element 790 may further be set in a position that isolates theair spring 730 a from all other components of air management system 700such that the air pressure of the air spring 730 a remains static.

In another configuration (not shown), the throttle element is configuredto rotate about the longitudinal axis of the manifold in response toreceiving an electric signal. By rotating about the longitudinal axis ofthe manifold, the manifold is configured to control exposure of thefirst, second, and third openings such that the valve 746 a isconfigured to selectively supply or remove air from the chamber of theair spring. The valve 746 a may include an electronic actuatorconfigured to trigger movement of the throttle element along thelongitudinal axis of the manifold.

In another configuration (not shown), the manifold includes a pluralityof openings disposed along a surface of the manifold. The plurality ofopenings include a first opening disposed approximate a first end of themanifold, a second opening disposed approximate a second end of themanifold, a third opening disposed between the first and second openingsand disposed on an opposite side of the manifold to the first and secondopenings, and a fourth opening disposed between the first and secondopenings. The first opening is in direct pneumatic communication withthe inlet port 741 a. The second opening is in direct pneumaticcommunication with the outlet port 742 a. The third opening is in directpneumatic communication with the delivery port 744 a. The fourth openingis in direct pneumatic communication with the cross-flow port 143 a. Inone configuration, the throttle element is configured to receive anelectric signal and slide along the longitudinal axis of the manifold inresponse to receiving an electric signal. By sliding along thelongitudinal axis of the manifold, the throttle element is configured tocontrol the exposure of the first, second, third, and fourth openingssuch that the valve 746 a is configured to selectively supply air,remove air, or establish cross-flow for the associated air spring 730 a.The displacement of the throttle element further controls the rate ofair flow through the control unit 740 a. The throttle element mayfurther be set in a position that isolates the air spring from all othercomponents of air management system 700 such that the air pressure ofthe air spring remains static.

In another configuration (not shown), the throttle element is configuredto rotate about the longitudinal axis of the manifold in response toreceiving an electric signal. By rotating about the longitudinal axis ofthe manifold, the manifold is configured to control exposure of thefirst, second, and third openings such that the valve 746 a isconfigured to selectively supply or remove air from the chamber of theair spring. The valve 746 a may include an electronic actuatorconfigured to trigger movement of the throttle element along thelongitudinal axis of the manifold.

The control unit 740 a comprises one or more sensors 748 a, acommunication interface 749 a, and a processing module 750 a operativelylinked to the one or more sensors 748 a and the communication interface749 a. In some configurations, the control unit 740 a may comprise apower source (not shown), such as a rechargeable battery and/or asupercapacitor integrated with the housing 780 a of the control unit 740a or external to the housing 780 a of the control unit 740 a, to provideoperating power to the one or more sensors, communication interface, andprocessing module. The power source may be operatively linked to thepower supply of the vehicle to receive a recharging current. In otherconfigurations (not shown), the housing of the control unit 740 a mayextend above the top plate such that the valve chamber, the valve, andthe processing module are mounted above the top plate and disposedoutside the chamber of the air spring.

The one or more sensors 748 a may be any suitable configuration ordevice for sensing a condition of the vehicle or any of the componentsof the air management system. In one example, the one or more sensors748 a include a height sensor configured to continuously monitor theaxial distance between the top plate 732 a and a base plate 734 a of theair spring 730 a. The height sensor is configured to generate a signalindicating a height or distance associated with the air spring 730 a,such as the axial distance between the top plate 732 a and the baseplate 734 a. In one configuration, the height sensor may be a ultrasonicsensor, in which sensor transmits ultrasonic waves, detects the wavesreflected from base plate 734 a, and determines the axial separationbetween the top and base plate based on the detected waves. In anotherconfiguration, the height sensor may be an infrared sensor, in which thesensor transmits an infrared light by a transmitter, receives areflected infrared light by a receiver, and determines the axialseparation between the top and base plates based on the amount ofinfrared radiation reflected back to the receiver. The height sensor maybe any other suitable type or configuration for monitoring the height ofthe air spring 730 a, such as a potentiometer, linear positiontransducer, a laser sensor, or an electromagnetic wave sensor. Inanother example, the one or more sensors may include a pressure sensorconfigured to continuously monitor the internal air pressure of the airspring 730 a and generate a signal indicating the internal air pressureof the air spring 730 a. In one configuration, the pressure sensor is apressure transducer.

The communication interface 749 a may be any suitable device orcomponent for relaying analog or digital signals to, from, and betweenthe processing module 750 a and the control units 740 a of other airsprings 730 a of the air management system 700 a and/or other vehicleoperating systems. In the illustrated configuration shown in FIG. 19,the air spring 730 a includes a plurality of leads 735 a that connectthe control unit 740 a to the control units 740 a of other air springs730 a of the air management system 700 a and other vehicle operatingsystems, such as a CAN, RSC, ESC, ABS, PTC, AEB, collision avoidancesystems, etc. The communication interface 749 a is configured to receiveany signals received from the wired leads 735 a and relay those signalsto the processing module 750 a. The communication interface 749 a isconfigured to receive any signals generated by the processing module 750a and transmit those signals over the wired leads to the control units740 a of other air springs 730 a of the air management system 700 andother vehicle operating systems. Accordingly, the control unit 740 a foreach air spring 730 a may be in electrical communication with thecontrol units 740 a of the other air springs 730 a of the air managementsystem 700 such that the control unit may directly transmit and receivedata or commands to and from the control units 740 a of the other airsprings 730 a without relaying the signals through other systemcomponents.

The processing module 750 a of the control unit 740 a may be anysuitable device or component for receiving input signals from the one ormore sensors 748 a and the communication interface 749 a and outputtingcommands to adjust height of the air spring 730 a to a desired heightbased on the received input signals. The processing module 750 a maycomprise one or more processors, central processing units, applicationspecific integrated circuits, microprocessors, digital signalprocessors, microcontrollers or microcomputers. The processing module750 a may further comprise memory, such as read-only memory, to storeall necessary software that embodies the control strategy andmathematical formulations for the operation of the control unit 740 a.The processing module 750 a may comprise an oscillator and clock circuitfor generating clock signals that allow the processing module 750 a tocontrol the operation of the control unit 740 a. The processing module750 a may comprise a driver module, such as a driving circuit,operatively linked to the valve such that the processing module mayselectively actuate valve. The processing module 750 a may signal thedriver module to actuate the valve in any suitable manner, such as bypulse width modulation or hit-and-hold actuation. For example, theprocessing module 750 a may alter the rotation of the valve bymodulating the electronic signal transmitted from the driver module tothe electronic actuator of the valve. The processing module 750 a maycomprise a sensor interface for receiving signals generated by the oneor more sensors. The processing module 750 a may comprise ananalog-to-digital converter linked to the sensor interface so thatanalog signals received from the one or more sensors may be converted todigital signals. In turn, the digital signals are processed by theprocessing module 750 a to determine one or more conditions of the airspring 730 a, such as spring height or internal air pressure.Accordingly, the processing module 750 a is configured to receive allthe necessary inputs to calculate a desired air pressure for the airspring 730 a, determine the necessary air flow rate to alter the airpressure of the air spring 730 a, and convey commands in terms ofsupplying or purging air to the valve 746 a of the control unit 740 a.

The control unit 740 a operates as a closed-loop control system toadjust the height of its associated air spring 730 a to a desired heightbased on the monitored operating conditions of the vehicle. Inoperation, the processing module 750 a receives inputs from the one ormore sensors 748 a, such as the height sensor and the pressure sensor,to determine the height and the internal air pressure of the air spring730 a. The processing module 750 a commands the communication interface749 a to transmit signals indicating the spring height and the internalair pressure of the air spring 730 a to the control units 740 a of theother air springs 730 a of the air management system 700 a. In return,the communication interface 749 a may receive data signals from thecontrol units 740 a of the other air springs 730 a and relay those datasignals as inputs to the processing module 750 a. The processing module750 a then determines the desired air pressure for its associated airspring 730 a based on inputs from the one or more sensors 748 a and datasignals received from the other air springs 730 a of the air managementsystem 700. In determining the desired air pressure for its associatedair spring 730 a, the processing module 750 a may take into account thedifferences in air pressures between all the air springs 730 a of theair management system 700 a so that the processing module 750 a maydetermine the vehicle pitch and roll rates. The processing module 750 adetermines the flow rate needed to adjust the internal air pressure ofits associated air spring 730 a based on the vehicle roll and pitchrates. In one configuration, the calculated flow rate is based on howfast the height of the air spring 730 a is changing in response to aload or displacement (i.e., height differential rate). Based on theheight differential rate and the internal pressure of the air spring 730a and the differences between heights of the air springs 730 a of theair management system 700 a, the processing module 750 a is configuredto determine the desired air pressure and flow rate needed to adjust theair spring 730 a to provide optimal stability and comfort for thevehicle. After determining the desired air pressure and flow rate, theprocessing module 750 a is configured to control the flow rate of airbeing exhausted from or supplied to its associated air spring 730 a.While each control unit 740 a may determine the desired air pressure forits associated air spring 730 a based at least partly on the springheights of the other air springs 730 a, each control unit 740 a actsindependent to other control units 740 a of the air management system.Accordingly, the air pressure for each air spring 730 a of the airmanagement system may be adjusted at a different rate, which ultimatelyorients the vehicle in a stable position at a faster rate.

In one configuration, each control unit 740 a is configured to providecross-flow between the first and second pneumatic circuits 710 a, 720 awhen neither air is supplied from the supply tank 704 a to the airsprings 730 a nor air is removed from the air springs 730 a to theatmosphere. In operation, each time that the processing module 750 adetermines that the height or the air pressure of its associated airspring 730 a does not need to be adjusted independently, the processingmodule 750 a actuates the valve 746 a to switch to its neutral stateestablishing pneumatic communication between the delivery port 744 a andthe cross-flow port 743 a. The processing module 750 a may determine toactuate the valve 746 a to its neutral mode based on sensor inputsignals from its associated sensors 748 a and data signals from thecontrol units 740 a of the other air springs 730 a. In oneconfiguration, the processing module 750 a is configured to take intoaccount a difference between a spring height of its associated airspring 730 a and a second spring height of the second air spring 730 ain determining to actuate the valve between the active mode and theneutral mode. In one configuration, the processing module 750 a isconfigured to take into account a difference between the air pressure ofits associated air spring 730 a and a second air pressure of the secondair spring 730 a in determining to actuate the valve 746 a between theactive mode and the neutral mode. Once each control unit 740 a actuatesits associated valve 746 a to its neutral mode, then pneumaticcommunication is established between the air spring 730 a in the firstpneumatic circuit 710 a and the air spring 730 a in the second pneumaticcircuit 720 a via the cross-flow line 760 a. Accordingly, pressuredifferences between air springs 730 a disposed on opposite sides of thevehicle are eliminated, providing a more stable ride for the vehicle. Invarious embodiments, the control unit 740 is configured to providecross-flow between the first and second pneumatic circuits when thevehicle is traveling at any speed, include velocities substantiallyabove zero miles-per-hour or kilometers-per-hour, so that the pressuredifferences between air springs 730 a disposed on opposite sides of thevehicle are eliminated at any time during vehicle operation.

In one configuration, the processing module 750 a is configured toreceive measurement signals, such as height and pressure measurements ofthe air spring 730 a, from the one or more sensors 748 a and datasignals from the communication interface 749 a. The data signals mayinclude measurement signals from control units 740 a of other airsprings 730 a of the air management system 700. Based on the measurementand data signals, the processing module 750 a is configured to calculatea current state of its associated air spring 730 a, the current state ofthe other air springs 730 a of the air management system 700, and adynamic operating state of the vehicle. Based on the calculated currentstates of the air springs 730 a and the dynamic operating state of thevehicle, the processing module 750 a is configured to determine toactuate the valve 746 a between the active mode and the neutral mode. Inone configuration, the processing module 750 a is configured tocalculate a pressure differential or a height differential between theair springs 730 a of the air management system 400 based on the receivedmeasurement and data signals. The processing module 750 a is configuredto actuate the valve 746 a in the active mode when the pressuredifferential or the height differential between the air springs 730 a isabove a predetermined threshold and actuate the valve in a neutral modewhen the pressure differential or height differential is below apredetermined threshold. Accordingly, when there is a substantial heightdifference between respective sides of the vehicle, the control unit 740a is configured to independently adjust the height of its air spring tobring the vehicle to a level condition at a faster rate. The controlunit 740 a may actuate the valve 746 a in an active mode at any vehiclespeed. On the other hand, when there is only a slight heightdifferential between the respective sides of the vehicle that does nottrigger a rolling condition, the control unit 740 a is configured tomitigate any pressure differential between the air springs byestablishing cross-flow between the air springs. The control unit 740 amay actuate the valve in a neutral mode at any vehicle speed.

The current state of an air spring may include the current height of theair spring, the current internal pressure of the air spring, the heightdifferential rate of the air spring, and/or the internal pressuredifferential rate of the air spring. The dynamic operating state of thevehicle may include the vehicle pitch rate and the vehicle roll rate.Vehicle pitch is a relative displacement between the front and rear of avehicle, which may be represented by a rotation about a lateral axispassing through the center of mass of the vehicle. Accordingly, thevehicle pitch rate refers to the angular motion velocity of the vehicleabout its lateral axis, the axis extending from one side to the oppositeside of the vehicle. Vehicle roll is a relative displacement between twosides of a vehicle, which may be represented by a rotation about alongitudinal axis passing through the center mass of the vehicle.Accordingly, the vehicle roll rate refers to the angular motion velocityof the vehicle body relative to its longitudinal axis, i.e., the axisthat extends from the back of the vehicle to front.

FIG. 20 shows an air management system 700 b comprising a supply airtank 704 b, a first pneumatic circuit 710 b disposed on a first side ofthe vehicle, and a second pneumatic circuit 720 b disposed on a secondside of the vehicle. Each pneumatic circuit 710 b, 720 b, includes oneor more air springs 730 b. Each air spring 730 b comprises a controlunit 740 b disposed within a chamber of the air spring 730 b. The airmanagement system 700 b further comprises a system controller 770 thatis operatively linked to the air springs 730 b. The system controller770 allows the air management system 700 b to selectively supply air toor remove air from each air spring 730 b of the air management system700 b. As shown in FIG. 20, a cross-flow line 760 b connects the controlunit 740 b of an air spring 730 b in the first pneumatic circuit 710 bto a control unit 740 b of an air spring 730 b in the second pneumaticcircuit 720 b. The system controller 770 is configured to command eachcontrol unit 740 b to provide cross-flow between the two air springs 730b of the first and second pneumatic circuits 710 b, 720 b when neitherair is supplied from the supply tank 704 b to the air springs 730 b norair is removed from the air springs 730 b to the atmosphere, i.e., inthe neutral mode.

As shown in FIG. 23, the system controller 770 comprises a processingmodule 772 that may consist of one or more processors, centralprocessing units, application specific integrated circuits,microprocessors, digital signal processors, microcontrollers ormicrocomputers. The system controller 770 comprises memory 774, such asread-only memory or random-access memory, to store all necessarysoftware that embodies the control strategy and mathematicalformulations for the operation of the system controller. The systemcontroller 770 comprises a communication interface 776 for relayingsignals to, from, and between the processing module 772 and the controlunits of other air springs 730 b of the air management system 700 band/or other vehicle operating systems. The system controller 770comprises a bus 778 that couples the various components of the systemcontroller to the processing module 772. Accordingly, the systemcontroller 770 is configured to receive all the necessary inputs tocalculate a desired air pressure for each air spring 730 b of the airmanagement system 700 b, determine the necessary air flow rate to alterthe air pressure of each air spring 730 b of the air management system700 b, and convey commands in terms of supplying or purging air to thecontrol unit 740 b of each air spring 730 b of the air management system700 b.

Similar to the control unit 740 a shown in FIG. 22, the control unit 740b shown in FIG. 24 comprises an inlet port 741 b disposed along a firstsurface of the housing 780 b, an outlet port 742 b disposed along thefirst surface of the housing 780 b, a cross-flow port 743 b disposedalong a first surface of the housing 780 b, a delivery port 744 bdisposed along a second surface of the housing 780 b, a valve 746 bdisposed in a valve chamber 745 b, one or more sensors 748 b, acommunication interface 749 b, and a processing module 750 b operativelylinked to the one or more sensors 748 b and the communication interface749 b. The control unit 740 b differs from the control unit 740 a shownin FIG. 22 in that the communication interface 749 b comprises anantenna (not shown) that is configured to communicate wirelessly to thesystem controller 770.

The system controller 770 and the control units 740 b are linkedtogether to operate as a closed-loop control system to adjust the heightof each air spring 730 b to a desired height based on the monitoredoperating conditions of the vehicle. In operation, each control unit 740b transmits signals indicating the spring height and the internal airpressure of its associated air spring 730 b to the system controller770. In return, the system controller 770 determines the desired airpressure and the desired volumetric flow rate to remove and supply airto and from each air spring 730 b based on the signals received from thecontrol units 740 b. In determining the desired air pressure for eachair spring 730 b, the system controller 770 may take into account thedifferences in air pressures and spring heights between all the airsprings 730 b of the air management system 700 b. After determining thedesired air pressure and flow rate for each air spring 730 b, the systemcontroller 770 transmits commands to the control unit of each air spring730 b of the air management system 700 b, in which the command includesactuating the valves 746 b of each control unit 740 b between the activeand neutral modes.

In one configuration, the system controller 770 is configured to providecross-flow between the first and second pneumatic circuits 710 b, 720 bwhen neither air is supplied from the supply tank 704 b to the airsprings 730 b nor air is removed from the air springs 730 b to theatmosphere. In operation, each time that the system controller 770determines that the height of the air springs 730 b do not need to beadjusted independently, the system controller 770 transmits commandsignals to the control units 740 b to actuate its respective valve 746 bto its neutral mode. The system controller 770 may determine to commandeach control unit 740 b to switch to its neutral mode based on heightmeasurement signals received from the control units 740 b. Once eachcontrol unit 740 b actuates its associated valve 746 b to its neutralmode, then pneumatic communication is established between the air spring730 b in the first pneumatic circuit 710 b and the air spring 730 b inthe second pneumatic circuit 720 b via the cross-flow line 760 b.Accordingly, pressure differences between air springs 730 b disposed onopposite sides of the vehicle are eliminated, providing a more stableride for the vehicle.

FIG. 21A shows an air management system 800 comprising a supply air tank804, a first pneumatic circuit 810 disposed on a first side of thevehicle, and a second pneumatic circuit 820 disposed on a second side ofthe vehicle. Each pneumatic circuit 810, 820 includes one or more airsprings 830. The air management system 800 further comprises a systemcontroller 840 and a plurality of valves 850 operatively linked to thesystem controller 840. Referring to FIG. 21A, one of the valves 850 isdeposed in the first pneumatic circuit 810, and the other one of thevalves 850 is disposed in the second pneumatic circuit 820. The systemcontroller 840 allows the air management system 800 to selectivelysupply air to or remove air from each air spring 830 of the airmanagement system 800 by actuating the plurality of valves 850.

As shown in FIG. 21A, a cross-flow line 860 connects one valve 850 inthe first pneumatic circuit 810 to a valve 850 in the second pneumaticcircuit 820, thereby establishing a pneumatic connection between the airsprings 830 of the first and second pneumatic circuits 810, 820. Eachvalve 850 is configured to switch between a plurality of states,including a first mode in which air is released out of the air spring830, a second mode in which the air is supplied into the spring 830, aneutral mode in which the air spring 830 is pneumatically connected tothe cross-flow line 860. The system controller 840 is configured tocommand each valve 850 to switch to a neutral mode to provide cross-flowbetween the two air springs 830 of the first and second pneumaticcircuits 810, 820 when neither air is supplied from the supply tank 804to the air springs 830 nor air is removed from the air springs 830 tothe atmosphere.

Referring to FIG. 21A, a height sensor 870 is disposed in the top plate832 of each air spring 830 and is configured to continuously monitor theheight of its associated air spring 830. The height sensor 870 may beany suitable device for monitoring the axial height of the air spring,such as the examples described above. Each height sensor 870 is wired tothe system controller 840 so that each height sensor 870 may transmitsignals indicating the height of its associated air spring 830 to thesystem controller 840. In other configurations, the air managementsystem 800 may include an air pressure sensor disposed in the top plateof the 832 of each air spring 830. The air pressure sensor is configuredto monitor the air pressure of its associated air spring 830 andgenerate a signal indicating the air pressure of its associated airspring.

Similar to the system controller shown in FIG. 23, the system controller840 shown in FIG. 25 comprises a processing module 842 for determiningthe desired air pressure and flow rate for each air spring 830 of theair management system 800, a communication interface 8464 for relayingsignals to and from the processing module 842 and the height sensors ofthe air springs 830, a memory 844 for storing all necessary softwarethat embodies the control strategy and mathematical formulations for theoperation of the system controller 840, and a bus 848 connecting thecommunication interface 846 and memory 84 to the processing module 842.The system controller 840 further comprises a driver module 845, such asa driving circuit, operatively linking the processing module 842 to eachvalve 850 such that the system controller 840 may selectively actuatevalve 850. The processing module 842 of the system controller 840 maysignal the driver module 845 to actuate the valve 850 in any suitablemanner, such as by pulse width modulation or hit-and-hold actuation.Accordingly, the system controller 840 is configured to receive all thenecessary inputs to calculate a desired air pressure for each air springof the air management system 800, determine the necessary air flow rateto alter the air pressure of each air spring 830 of the air managementsystem 800, and actuate at least one of the valves 850 to adjust the airpressure and height of at least one of the springs 830 of the airmanagement system 800.

In one configuration, the system controller 840 is configured to providecross-flow between the first and second pneumatic circuits 810, 820 whenneither air is supplied from the supply tank 804 to the air springs 830nor air is removed from the air springs 830 to the atmosphere. Inoperation, each time that the system controller 840 determines that airdoes not need to be removed or added to the air springs 830, the systemcontroller 840 actuates each valve 850 to its neutral mode. The systemcontroller 840 may determine to actuate the valves 850 to the neutralmode when the pressure differentials between the air springs 830 arewithin a predetermined tolerance. The system controller 840 maycalculate the pressure differentials between the air springs 830 basedon signals received from the pressure sensors of the air springs 830.The system controller 840 may determine to actuate the valve 850 to itsneutral mode based on height measurement signals received from theheight sensors 870. The system controller 840 may take into account theheight differences between the air springs 830 when determining whetherto actuate the valves to an active mode (i.e., the first or secondmodes) or a neutral mode. Once each valve 850 is actuated to its neutralmode, then pneumatic communication is established between the air spring830 in the first pneumatic circuit 810 and the air spring 830 in thesecond pneumatic circuit 820 via the cross-flow line 860. Accordingly,pressure differences between air springs 830 disposed on opposite sidesof the vehicle are eliminated, providing a more stable ride for thevehicle.

FIG. 21B illustrates an air management system 800′ according to oneconfiguration of the present invention. The air management system 800′is similar to the air management system 800 of FIG. 21A except that thesystem controller 840′ comprises a single valve 850′ that ispneumatically connected to each air spring 830 of the air managementsystem 800′. Accordingly, the system controller 840′ may selectivesupply or remove air from the air springs 830 through the use of onlyone valve 850′. In one configuration, the system controller 840′ isconfigured to calculate a difference between the air pressures of theair springs 830 based on received measurement signals from the sensor.If the system controller 840′ determines that the difference between theair pressures of the air springs 830 is within a predeterminedtolerance, then system controller 840′ actuates the valve 850′ to setthe air pressure of each air spring 830 to the same air pressure.

In each configuration of the air management system shown in FIGS.19-21B, the control units or the system controller may be configured toexecute a dump cycle such that the air is released from each air springof the air management at the same time. In each air management systemshown in FIGS. 19-21B, the air management system may include a userinterface unit operatively linked to the control units or the systemcontroller and configured transmit a command to the system controller orthe control units to execute a dump cycle so that air is released fromall the air springs. The user interface unit may be disposed in thevehicle dashboard or configured as an application downloaded on adisplay device, such as a smartphone or hand-held computer.

All the configurations of the air management systems described hereinmay be incorporated with any type of vehicle, trailer, or towable,including but not limited to, sport-utility vehicles, passengervehicles, racing vehicles, pick-up trucks, dump trucks, freightcarriers, trailers of any type including trailers for boats, cattle,horses, heavy equipment, tractors, agriculture implements (e.g.,granular spreaders, fertilizer sprayers and other types of sprayers,feeders and spreaders), liquid hauling vehicles, baffled and unbaffledliquid tankers, machinery, towing equipment, rail vehicles, road-railvehicles, street cars, and any other type of chassis having air bags,etc.

The air management systems described herein have been found tosignificantly increase tire life both in terms of reducing wear andresulting in even wear, even when the tires are not rotated. In oneexemplary embodiment, it has been observed that truck tires having anaverage life of 100,000 km when mounted on trucks that were not equippedwith the air management systems described herein, experiencesignificantly reduced wear when mounted on identical trucks that areequipped with the air management systems described herein. In certainembodiments, average truck tire life is extended by at least 20%, and insome instances by up to 30%, 40%, 50%, or more. As such, an unexpectedand significant financial, time (reduced time waste in rotating,changing, retreading, and replacing tires), and environmental savings isrealized as additional surprising advantages of the inventions of thisdisclosure.

The air management systems described herein have been found tosignificantly reduce the unsafe effects of wind shears on vehiclestraveling at speed, particularly on truck trailers. Wind shearsdestabilize trucks hauling trailers at highway speeds and have causedsuch trailers to overturn leading to devastating injuries and losses oflife, cargos, and multi-vehicle wrecks. In one exemplary embodiment,trailers and recreational vehicles that are equipped with the airmanagement systems described herein may be significantly more stable andresistant to wind shear forces at highway speeds. As such, an unexpectedand significant safety and comfort advantage is realized as additionalsurprising advantages of the inventions of this disclosure.

The air management systems described herein have been found tosignificantly reduce road noise, vibrations, and discomfort for drivers,passengers as well as live cargo including livestock, horses and thelike. In one exemplary embodiment, it has been observed that road noise,vibrations, and discomfort are significantly reduced such that driversthat could previously drive large vehicles only a few hundred miles perday due to discomfort were able to drive significantly longer distancesdue to the reduction in aches, pains, discomfort and fatigue, which wasachieved from very noticeably improved ride quality and stability. Assuch, an unexpected and significant comfort advantage is realized asadditional surprising advantages of the inventions of this disclosure.

The air management systems described herein have been found tosignificantly reduce or even eliminate vehicle nose-diving when braking.Such nose-diving can create unsafe conditions, is highly uncomfortablefor drivers and passengers, and puts increased stress on numerousvehicle components. By reducing and in many cases eliminating suchnose-diving, an unexpected and significant safety and comfort advantageis realized as additional surprising advantages of the inventions ofthis disclosure.

The air management systems described herein have been found tosignificantly increase traction resulting in improved handling, even inslippery conditions. In one exemplary embodiment, it has been observedthat trucks requiring use of four-wheel drive mode (when not equippedwith the air management systems described herein) to drive throughuneven and/or slippery terrain were able to be drive through the sameterrain in two-wheel drive mode without losing traction and becomingimmobilized. As such, an unexpected and significant safety and utilityadvantage is realized as additional surprising advantages of theinventions of this disclosure.

The air management systems described herein may enhance brakeperformance. In vehicles equipped with electronic stability systems,e.g., any electronic stability control (ESC), including, but not limitedto electronic stability program (ESP), dynamic stability control (DSC),vehicle stability control (VSC), automatic traction control (ATC), theair management systems described herein have been found to reduce theincidence rate of such electronic systems applying brakes because thevehicle is maintained in a level and stable position, and thereby avoidsactivation of such electronic systems, which may enhance brakeperformance and life.

In the present context, the phrase “adjust independently” refers to astate in which the leveling valve is adjusting the air pressure of airsprings in one pneumatic circuit while the leveling valve is not inpneumatic communication with any components of another pneumaticcircuit.

As used herein, the terms “substantially” and “substantial” refer to aconsiderable degree or extent. When used in conjunction with, forexample, an event, circumstance, characteristic, or property, the termscan refer to instances in which the event, circumstance, characteristic,or property occurs precisely as well as instances in which the event,circumstance, characteristic, or property occurs to a closeapproximation, such as accounting for typical tolerance levels orvariability of the examples described herein.

As used herein, the term “about” when used in connection with anumerical value should be interpreted to include any values which arewithin 5% of the recited value. Furthermore, recitation of the termabout and approximately with respect to a range of values should beinterpreted to include both the upper and lower end of the recitedrange.

As used herein, the terms “attached,” “connected,” or “fastened.” may beinterpreted to include two elements that are secured together with orwithout contacting each other.

The present disclosure includes methods, kits, and systems forretrofitting vehicles that have been manufactured without air springsincluding but not limited to coil spring or leaf spring suspensionsystems. A symmetrically dynamic equalized volume and pressuredistributing air management system may be installed as a retrofit onsuch vehicles by providing a kit comprising an air tank, a compressor, asymmetrically dynamic equalized volume and pressure distributingpneumatic valve on each of the left and right sides of the vehicle, atleast one air spring connected to each symmetrically dynamic equalizedvolume and pressure distributing pneumatic valve, and a plurality of airhoses connecting the air management system components as described andillustrated herein. In some configurations of the present disclosure,the plurality of air hoses may have equal lengths and diameters.

In the appended claims, the term “including” is used as theplain-English equivalent of the respective term “comprising.” The terms“comprising” and “including” are intended herein to be open-ended,including not only the recited elements, but further encompassing anyadditional elements. Moreover, in the following claims, the terms“first,” “second,” and “third,” etc. are used merely as labels, and arenot intended to impose numerical requirements on their objects. Further,the limitations of the following claims are not written inmeans-plus-function format and are not intended to be interpreted basedon 35 U.S.C. § 112(f), unless and until such claim limitations expresslyuse the phrase “means for” followed by a statement of function void offurther structure.

Various embodiments of the invention comprise one or more of thefollowing items:

1. An air management system for a vehicle, the air management systemcomprising: a first pneumatic circuit having a first leveling valveconfigured to adjust independently the height of a first side of thevehicle; a second pneumatic circuit having a second leveling valveconfigured to adjust independently the height of a second side of thevehicle; and a cross-flow line connecting the first leveling valve withthe second leveling valve; wherein the first and second leveling valvesare configured to establish pneumatic communication between the firstand second pneumatic circuits when the first leveling valve is notindependently adjusting the height of the first side of the vehicle andthe second leveling valve is not independently adjusting the height ofthe second side of the vehicle.

2. The air management system of item 1, wherein the first and secondleveling valves each include a housing body and a control arm pivotablyconnected to a shaft extending through the housing body, and the controlarm is configured to pivot from a neutral position to one or moreresponse positions.

3. The air management system of items 1 or 2, wherein the first andsecond leveling valves are configured to establish pneumaticcommunication between the first and second pneumatic circuits when thecontrol arm of both the first and second level valves are set in theneutral position, and the first and second leveling valves areconfigured to prevent pneumatic communication between the first andsecond pneumatic circuits when the control arm of one of the first andsecond leveling valves is set to the one or more response positions.

4. The air management system of any of items 1-3, wherein the first andsecond leveling valves each include a control arm sensor configured todetect the position of the control arm.

5. The air management system of any of items 1-4, further comprising acontrol unit in electrical communication with each control arm sensor,wherein each control arm sensor is configured to transmit the positionof the control arm as a control arm position input to the control unit,and the control unit is configured to determine a vehicle heightrelative to the axle at the first and second sides of the vehicle basedon the control arm position input.

6. The air management system of any of items 1-5, wherein the firstpneumatic circuit comprises a first set of air springs disposed on afirst side of the vehicle, a first supply tank, a first plurality of airlines pneumatically connecting the first set of air springs with thefirst leveling valve, and a first supply line pneumatically connectingthe first leveling valve with the first supply tank; and the secondpneumatic circuit comprises a second set of air springs disposed on asecond side of the vehicle, a second supply tank, a second plurality ofair lines pneumatically connecting the second set of air springs withthe second leveling valve, and a second supply line pneumaticallyconnecting the second leveling valve with the second supply tank.

7. The air management system of any of items 1-6, wherein the firstplurality of air lines and the second plurality of air lines being ofthe substantially the same diameter and length, and the first supplyline and the second supply line being of substantially the same diameterand length.

8. The air management system of any of items 1-7, wherein the first andsecond leveling valves are each rotary valves comprising a housing bodyand a rotary disk configured to rotate within the housing body to altercommunication between the between the first and second pneumaticcircuits.

9. The air management system of any of items 1-8, wherein the first andsecond leveling valves each include a manifold housing, a valve elementdisposed in a bore of the manifold housing, and an electronic actuator,wherein the valve element is configured to move in the bore of themanifold housing to one or more positions including at least a neutralposition to establish pneumatic communication between the first andsecond pneumatic circuits and a supply position to supply air to arespective pneumatic circuit from an air supply tank, and an exhaustposition to remove air from the respective pneumatic circuit into theatmosphere, and the electronic actuator is configured to triggermovement of the plunger between the one or more positions.

10. The air management system of any of items 1-9, wherein the valveelement is selected from the group consisting of a plunger, a rotarydisk, and a poppet.

11. The air management system of any of items 1-10, wherein theelectronic actuator is selected from the group consisting of a solenoid,a servomotor, and a stepper motor.

12. The air management system of any of items 1-11, further comprising acontrol module in electrical communication with the electronic actuatorof each leveling valve, wherein the control module is configured totransmit a command to each electronic actuator to trigger movement ofthe valve element between the neutral, supply, and exhaust positions.

13. The air management system of any of items 1-12, further comprisingone or more leveling sensors, wherein each leveling sensor is configuredto detect vehicle height relative to the axle along a position of thevehicle and transmit the detected vehicle height to the control moduleas a vehicle leveling input, and the control module is configured todetermine a vehicle height relative to the axle at the first and secondsides of the vehicle based on the vehicle leveling input.

14. The air management system of any of items 1-13, wherein the firstpneumatic circuit comprises one or more air springs, and the secondpneumatic circuit comprises one or more air springs; and wherein thefirst leveling valve and the second leveling valve are each anelectronically-actuated valve disposed in a chamber of a respective airspring.

15. The air management system of any of items 1-14, wherein the firstand second leveling valves each include, a cylindrical-shaped manifold,a valve member disposed in the manifold and in sliding engagement withan interior surface of the manifold, and an electronic actuatoroperatively linked to the valve member; wherein the manifold comprises aplurality of openings disposed along a side surface of the manifold, andthe electronic actuator is configured to actuate the valve member toslide along the longitudinal axis of the manifold to control theexposure of the plurality of openings such that a respective levelingvalve is configured to selectively: (i) supply air to a respectivepneumatic circuit, (ii) remove air from a respective pneumatic circuit,or (iii) establish cross-flow between the first and second pneumaticcircuits.

16. A leveling valve comprising: an upper housing mounted on a lowerhousing to form a valve body, wherein the valve body defines a chamberextending between the upper housing and the lower housing; the lowerhousing comprising a plurality of ports communicating with the chamber,wherein the plurality of ports include a supply port, an exhaust port,one or more spring ports, and a cross-flow port; a control arm having afirst end attached to a shaft extending through an upper surface of theupper housing, wherein the control arm is configured to rotate about thevalve body in response to extension or compression of the vehiclesuspension; a rotary disk positioned in the chamber of the valve bodyand connected to the control arm by the shaft, wherein the rotary diskis configured to rotate about the supporting element within the chamberof the valve body; and wherein the rotary disk is configured toestablish communication between the one or more spring ports and thecross-flow port while neither establishing communication between the oneor more spring ports and the supply port nor the one or more springports and the exhaust port.

17. The leveling valve of item 16, wherein the lower housing comprises adump port, wherein the cross-flow port is disposed on a first side ofthe lower housing and the dump port is disposed on a second side of thelower housing opposite to the first side.

18. The leveling valve of any of items 16-17, wherein the control arminduces the rotary disk to rotate between a plurality of angularpositions to alter communication between the supply port, the exhaustport, the one or more spring ports, and the cross-flow port, wherein theplurality of angular positions include (i) a neutral position, in whichthe one or more spring ports pneumatically communicate with thecross-flow port, and neither the supply port nor the exhaust portpneumatically communicates with the one or more spring ports, (ii) asupply position, in which the one or more spring ports pneumaticallycommunicate with the supply port, and neither the exhaust port nor thecross-flow port pneumatically communicates with the one or more springports, and (iii) an exhaust position, in which the one or more springports pneumatically communicate with the exhaust port, and neither thesupply port nor the cross-flow port pneumatically communicates with theone or more spring ports.

19. The leveling valve of any of items 16-18, wherein the lower housingcomprises a first surface mating with a lower surface of the upperhousing, wherein the first surface defines a supply hole directlycommunicating with the supply port; an exhaust hole directlycommunicating with the exhaust port; a reservoir cavity directlycommunicating with the one or more spring ports.

20. The leveling valve of any of items 16-19, wherein the rotary diskcomprises a central aperture for receiving the shaft, a plurality ofoblong-shaped slots, and a cross-flow slot, wherein the plurality ofoblong-shaped slots and cross-flow slot are spaced around the centralaperture with dead band defined there between and along the periphery ofthe rotary disk.

21. The leveling valve of any of items 16-20, wherein each oblong-shapedcavity is configured to at least partially overlie the reservoir cavityof the lower housing and the cross-flow slot over is configured tooverlie the cross-flow hole of the lower housing when the rotary disk isset at the neutral position.

22. The leveling valve of any of items 16-20, wherein the oblong-shapedslots are symmetrically spaced from a central axis extending along aface of the rotary disk, and the cross-flow slot overlies the centralaxis.

23. A method for controlling stability of a vehicle comprising:providing an air management system comprising: a first pneumatic circuithaving a first leveling valve configured to adjust independently theheight of a first side of the vehicle; a second pneumatic circuit havinga second leveling valve configured to adjust independently the height ofa second side of the vehicle; and a cross-flow line connecting the firstleveling valve with the second leveling valve; establishing, by thefirst and second leveling valves, pneumatic communication between thefirst and second pneumatic circuits when the first leveling valve is notindependently adjusting the height of the first side of the vehicle andthe second leveling valve is not independently adjusting the height ofthe second side of the vehicle.

24. The method of item 23, wherein the first and second leveling valveseach include a housing and a control arm pivotably connected to a shaftextending through the housing, and the control arm is configured topivot from a neutral position to one or more response positions.

25. The method of item 24, further comprising: establishing, by thefirst and second leveling valves, pneumatic communication between thefirst and second pneumatic circuits when the control arm of both thefirst and second level valves are set in the neutral position, andpreventing, by the first and second leveling valves, pneumaticcommunication between the first and second pneumatic circuits when thecontrol arm of one of the first and second leveling valves is set to theone or more response positions.

26. The method of any of items 23-25, wherein the first pneumaticcircuit comprises a first set of air springs disposed on a first side ofthe vehicle, a first supply tank, a first plurality of air linespneumatically connecting the first set of air springs with the firstleveling valve, and a first supply line pneumatically connecting thefirst leveling valve with the first supply tank; and the secondpneumatic circuit comprises a second set of air springs disposed on asecond side of the vehicle, a second supply tank, a second plurality ofair lines pneumatically connecting the second set of air springs withthe second leveling valve, and a second supply line pneumaticallyconnecting the second leveling valve with the second supply tank.

27. The method of any of items 23-26, wherein the first plurality of airlines and the second plurality of air lines being of the substantiallythe same diameter and length, and the first supply line and the secondsupply line being of substantially the same diameter and length.

28. The method of any of items 23-27, wherein the first pneumaticcircuit comprises one or more air springs, and the second pneumaticcircuit comprises one or more air springs; and wherein the firstleveling valve and the second leveling valve are each anelectronically-actuated valve disposed in a chamber of a respective airspring.

29. The method of any of items 23-28, wherein the first and secondleveling valves each include, a cylindrical-shaped manifold, a valvemember disposed in the manifold and in sliding engagement with aninterior surface of the manifold, and an electronic actuator operativelylinked to the valve member; wherein the manifold comprises a pluralityof openings disposed along a side surface of the manifold, and theelectronic actuator is configured to actuate the valve member to slidealong the longitudinal axis of the manifold to control the exposure ofthe plurality of openings such that a respective leveling valve isconfigured to selectively: (i) supply air to a respective pneumaticcircuit, (ii) remove air from a respective pneumatic circuit, or (iii)establish cross-flow between the first and second pneumatic circuits.

30. A method for adjusting air pressure of an air management system of avehicle comprising one or more air supply tanks, a first pneumaticcircuit disposed on a first side of the vehicle, and a second pneumaticcircuit disposed on a second side of the vehicle, the method comprising:adjusting independently the air pressure of the first pneumatic circuitby a first leveling valve such that the first leveling valve is eithersupplying air from the one or more air supply tanks to the firstpneumatic circuit or removing air from the first pneumatic circuit tothe atmosphere, adjusting independently the air pressure of the secondpneumatic circuit by a second leveling valve such that the secondleveling valve is either supplying air from the one or more air supplytanks to the second pneumatic circuit or removing air from the secondpneumatic circuit to the atmosphere, and establishing pneumaticcommunication between the first pneumatic circuit and the secondpneumatic circuit only when both the first leveling valve and the secondleveling valve are set in a neutral mode such that each leveling valveis neither supplying air from the one or more air supply tanks orremoving air into the atmosphere.

31. The method of item 30, wherein each leveling valve includes ahousing body comprising a supply port connected to the air supply tank,an exhaust port for purging air into the atmosphere, one or more portsconnected to one or more air springs, and a cross-flow port connected tothe other one of the first or second leveling valves.

32. The method of item 31, wherein each leveling valve includes a valveelement disposed in a chamber of the housing body and an actuatorconfigured to trigger movement of the valve element, wherein the valveelement is configured to move between a plurality of positions to altercommunication between the plurality of ports.

33. The method of item 32, wherein the plurality of positions include aneutral position to establish pneumatic communication between the firstand second pneumatic circuits, a supply position to supply air from theone or more air supply tanks to a respective pneumatic circuit, and anexhaust position to remove air from the respective pneumatic circuitinto the atmosphere.

34. The method of items 32 or 33, wherein the valve element is selectedfrom the group consisting of a plunger, a rotary disk, and a poppet.

35. The method of any of items 32-34, wherein the actuator is a controlarm pivotably connected to a shaft extending through the housing bodyand the valve element is a rotary disk.

36. The method of any of items 32-35, wherein the control arm isconfigured to pivot from a neutral position to one or more responsepositions, and each leveling valve is set in the neutral mode when thecontrol arm is set in the neutral position, and each leveling valve isadjusting independently the air pressure of a respective pneumaticcircuit when the control arm is set to the one or more responsepositions.

37. The method of any of items 32-36, wherein the actuator is anelectronic actuator selected from the group consisting of a solenoid, aservomotor, and a stepper motor.

38. The method of item 37, further comprising a control module inelectrical communication with the electronic actuator of each levelingvalve, wherein the control module is configured to transmit a command toeach electronic actuator to trigger movement of the valve elementbetween the plurality of positions.

39. The method of item 38, further comprising one or more levelingsensors, wherein each leveling sensor is configured to detect vehicleheight relative to the axle along a position of the vehicle and transmitthe detected vehicle height to the control module as a vehicle levelinginput, and the control module is configured to determine a vehicleheight relative to the axle at the first and second sides of the vehiclebased on the vehicle leveling input.

40. The method of any of items 30-39, wherein the first pneumaticcircuit comprises a first set of air springs disposed on the first sideof the vehicle, a first plurality of air lines pneumatically connectingthe first set of air springs with the first leveling valve, and a firstsupply line pneumatically connecting the first leveling valve with atleast one of the one or more air supply tanks; and the second pneumaticcircuit comprises a second set of air springs disposed on the secondside of the vehicle, a second plurality of air lines pneumaticallyconnecting the second set of air springs with the second leveling valve,and a second supply line pneumatically connecting the second levelingvalve with at least one of the one or more air supply tanks.

41. The method of any of items 30-40, wherein the first pneumaticcircuit comprises one or more air springs, and the second pneumaticcircuit comprises one or more air springs; and wherein the firstleveling valve and the second leveling valve are each anelectronically-actuated valve disposed in a chamber of a respective airspring.

42. A control unit associated with an air spring of an air managementsystem for a vehicle, the control unit comprising: a housing configuredto be mounted to a top plate of the air spring, wherein the housingcomprises a valve chamber; a valve disposed in the valve chamber,wherein the valve is configured to switch between a plurality of modesincluding: (i) an active mode wherein the valve is adjustingindependently a height of the associated air spring, and (ii) a neutralmode wherein the valve is establishing pneumatic communication betweenthe associated air spring and a cross-flow line connected to a secondair spring of the air management system when the valve is not in theactive mode; one or more sensors configured to monitor at least onecondition of the air spring and generate a measurement signal indicatingthe at least one condition of the air spring; a communication interfaceconfigured to transmit and receive data signals to and from a secondcontrol unit associated with the second air spring of the air managementsystem; and a processing module operatively linked to the valve, the oneor more sensors, and the communication interface; wherein the processingmodule is configured to: (i) receive measurement signals from the one ormore sensors and data signals from the communication interface, and (ii)actuate the valve to switch between the active mode and the neutral modebased on the received measurement signals from the one or more sensorsand the data signals from the communication interface.

43. The control unit of item 42, wherein the housing comprises: an inletport configured to receive air flow from an air source, an outlet portconfigured to release air to the atmosphere, a cross-flow portconfigured to connect to the cross-flow line connected to the second airspring of the suspension system and a delivery port configured to supplyor release air to and from a chamber of the air spring, wherein thevalve chamber is connected to the inlet port, the outlet port, and thedelivery port by a plurality of passages.

44. The control unit of items 42 or 43, wherein the one or more sensorscomprises a height sensor configured to monitor the height of the airspring and generate a signal indicating the height of the air spring.

45. The control unit of item 44, wherein the height sensor is anultrasonic sensor, an infrared sensor, an electromagnetic wave sensor,or a potentiometer.

46. The control unit of any of items 42-45, wherein the processingmodule is configured to take into account a difference between a springheight of its associated air spring and a second spring height of thesecond air spring in determining to actuate the valve between the activemode and the neutral mode.

47. The control unit of any of items 42-46, wherein the valve chamber,the valve, and the processing module are mounted below the top plate anddisposed in the chamber of the air spring.

48. The control unit of any of items 42-47, wherein the valve chamber,the valve, and the processing module are mounted above the top plate anddisposed outside the chamber of the air spring.

49. The control unit of any of items 42-48, wherein the valve comprisesa cylindrical-shaped manifold, a valve member disposed in the manifoldand in sliding engagement with an interior surface of the manifold, andan electronic actuator operatively linked to the valve member and theprocessing module; wherein the manifold comprises a plurality ofopenings disposed along a side surface of the manifold, and theelectronic actuator is configured to actuate the valve member to slidealong the longitudinal axis of the manifold to control the exposure ofthe plurality of openings such that the valve switches between theactive mode and neutral mode.

50. An air management system for a vehicle, the air management systemcomprising: a first pneumatic circuit having one or more air springsdisposed at a first side of a vehicle; a second pneumatic circuit havingone or more air springs disposed on a second side of a vehicle; and oneor more cross-flow lines, wherein each cross-flow line extends from anair spring associated with the first pneumatic circuit to an air springassociated with the second pneumatic circuit; wherein each air springcomprises a control unit, and each control unit comprises: a housingconfigured to be mounted to a top plate of an associated air spring,wherein the housing comprises a valve chamber; a valve disposed in thevalve chamber, wherein the valve is configured to switch between aplurality of modes including: (i) an active mode wherein the valve isadjusting independently a height of the associated air spring, and (ii)a neutral mode wherein the valve is establishing pneumatic communicationbetween the associated air spring and a respective cross-flow line whenthe valve is not in the active mode; one or more sensors configured tomonitor at least one condition of the associated air spring and generatea measurement signal indicating the at least one condition of theassociated air spring; a communication interface configured to directlytransmit and receive data signals to and from other control unitsassociated with other air springs of the suspension system; and aprocessing module operatively linked to the valve, the one or moresensors, and the communication interface; wherein the processing moduleis configured to: (i) receive measurement signals from the one or moresensors and data signals from the communication interface, and (ii)actuate the valve to switch between the active mode and the neutral modebased on the received measurement signals from the one or more sensorsand the data signals from the communication interface.

51. The air management system of item 50 comprising a system controllerin electrical communication with the communication interface of eachcontrol unit of the air management system, and wherein the systemcontroller is configured to: (i) receive measurement signals from eachcontrol unit of the air management system, (ii) determine a desiredvolumetric flow rate for removing or supplying air to and from thechamber of each air spring of the air management system based on thereceived measurement signals, and (iii) transmit commands to eachcontrol unit of the air management system such that each control unitactuates its associated valve between the active mode and the neutralmode.

52. The air management system of items 50 or 51, wherein the housingcomprises: an inlet port configured to receive air flow from an airsource, an outlet port configured to release air to the atmosphere, across-flow port configured to connect to the cross-flow line connectedto the second air spring of the air management system and a deliveryport configured to supply or release air to and from a chamber of theair spring, wherein the valve chamber is connected to the inlet port,the outlet port, and the delivery port by a plurality of passages.

53. The air management system of any of items 50-52, wherein the valvechamber, the valve, and the processing module are mounted below the topplate and disposed in the chamber of the air spring.

54. The air management system of any of items 50-53, wherein the valvechamber, the valve, and the processing module are mounted above the topplate and disposed outside the chamber of the air spring.

55. A method for controlling the stability of a vehicle comprising anair management system, wherein the air management system comprises afirst pneumatic circuit having one or more air springs disposed at afirst side of a vehicle; a second pneumatic circuit having one or moreair springs disposed on a second side of a vehicle; and one or morecross-flow lines, wherein each cross-flow line extends from an airspring associated with the first pneumatic circuit to an air springassociated with the second pneumatic circuit, the method comprising:monitoring, by a height sensor and an air pressure sensor, a height andan air pressure of a respective air spring; generating, by the heightsensor and air pressure sensor, a signal indicating the height and airpressure of the respective air spring; receiving, by a processingmodule, the signal indicating the height and air pressure of therespective air spring; calculating, by the processing module, a heightdifferential rate and pressure differential rate of the respective airspring based on the received signal indicating the height and airpressure of the respective air spring; determining, by the processingmodule, whether to adjust the height and air pressure of the air springindependently or establish pneumatic communication between the airspring and a respective cross-flow line; and actuating, by theprocessing module, a valve to switch to one of the modes: (i) an activemode wherein the valve is adjusting independently a height of theassociated air spring, and (ii) a neutral mode wherein the valve isestablishing pneumatic communication between the associated air springand a respective cross-flow line when the valve is not in the activemode; wherein the height sensor, processing module, and the valve aredisposed in a chamber of the air spring.

56. A method for reducing vehicle nose-diving when braking, avoidingrollover of a vehicle, trailer or towable due to wind shear or rapidlychanging road conditions, increasing tire life of a tire on a vehicle,reducing brake wear of a vehicle, and/or increasing traction of avehicle, comprising providing a vehicle equipped with an air managementsystem according to any of items 1-55; driving the vehicle underchanging road conditions; managing air in a plurality of pneumaticcircuits in the vehicle according to any of items 1-55 such that thevehicle experiences at least one of reduced vehicle nose-diving whenbraking, avoids rollover of the vehicle or a trailer or towable attachedthereto, increased tire life of a tire on the vehicle, reduced brakewear of the vehicle, and increased traction of the vehicle. 57. A kitcomprising two or more symmetrically dynamic equalized volume andpressure distributing pneumatic valve, at least one air springconfigured to be connected to each symmetrically dynamic equalizedvolume and pressure distributing pneumatic valve, a plurality of airhoses configured to be connect the air management components asdescribed and illustrated in any of items 1-56, and optionally an airtank, a compressor, pressure protection valve, and/or dump valve.

58. An air management system for a vehicle, the air management systemcomprising: a first pneumatic circuit having a first leveling valveconfigured to adjust independently the height of a first side of thevehicle; a second pneumatic circuit having a second leveling valveconfigured to adjust independently the height of a second side of thevehicle; and a cross-flow line connecting the first leveling valve withthe second leveling valve; wherein the first and second leveling valvesare configured to establish pneumatic communication between the firstand second pneumatic circuits when the first leveling valve is notindependently adjusting the height of the first side of the vehicle andthe second leveling valve is not independently adjusting the height ofthe second side of the vehicle; wherein the air management system isconfigured to perform the method of item 30.

59. The air management system of item 58 further comprising the subjectmatter of any one of items 2-14.

60. An air management system for a vehicle, the air management systemcomprising: a first pneumatic circuit having one or more air springsdisposed at a first side of a vehicle; a second pneumatic circuit havingone or more air springs disposed on a second side of a vehicle; and oneor more cross-flow lines, wherein each cross-flow line extends from anair spring associated with the first pneumatic circuit to an air springassociated with the second pneumatic circuit; wherein each air springcomprises a control unit, and each control unit comprises: a housingconfigured to be mounted to a top plate of an associated air spring,wherein the housing comprises a valve chamber; a valve disposed in thevalve chamber, wherein the valve is configured to switch between aplurality of modes including: (i) an active mode wherein the valve isadjusting independently a height of the associated air spring, and (ii)a neutral mode wherein the valve is establishing pneumatic communicationbetween the associated air spring and a respective cross-flow line whenthe valve is not in the active mode; one or more sensors configured tomonitor at least one condition of the associated air spring and generatea measurement signal indicating the at least one condition of theassociated air spring; a communication interface configured to directlytransmit and receive data signals to and from other control unitsassociated with other air springs of the suspension system; and aprocessing module operatively linked to the valve, the one or moresensors, and the communication interface; wherein the processing moduleis configured to: (i) receive measurement signals from the one or moresensors and data signals from the communication interface, and (ii)actuate the valve to switch between the active mode and the neutral modebased on the received measurement signals from the one or more sensorsand the data signals from the communication interface; wherein whereinthe air management system is configured to perform the method of item55.

61. The air management system of item 60 further comprising the subjectmatter of any one of items 52-54.

The present disclosure includes the ornamental design for a levelingvalve, its lower housing, its top housing, one or more rotary disks, ashaft, and any other embodiment of the present disclosure, as shown anddescribed.

While the subject matter of this disclosure has been described and shownin considerable detail with reference to certain illustrativeembodiments, including various combinations and sub-combinations offeatures, those skilled in the art will readily appreciate otherembodiments and variations and modifications thereof as encompassedwithin the scope of the present disclosure. Moreover, the descriptionsof such embodiments, combinations, and sub-combinations is not intendedto convey that the claimed subject matter requires features orcombinations of features other than those expressly recited in theclaims. Accordingly, the scope of this disclosure is intended to includeall modifications and variations encompassed within the spirit and scopeof the following appended claims.

The invention claimed is:
 1. A method for adjusting air pressure of anair management system of a vehicle comprising one or more air supplytanks, a first pneumatic circuit disposed on a first side of thevehicle, and a second pneumatic circuit disposed on a second side of thevehicle, the method comprising: adjusting independently the air pressureof the first pneumatic circuit by a first leveling valve such that thefirst leveling valve is either supplying air from the one or more airsupply tanks to the first pneumatic circuit or removing air from thefirst pneumatic circuit to the atmosphere, adjusting independently theair pressure of the second pneumatic circuit by a second leveling valvesuch that the second leveling valve is either supplying air from the oneor more air supply tanks to the second pneumatic circuit or removing airfrom the second pneumatic circuit to the atmosphere, and establishingpneumatic communication between the first pneumatic circuit and thesecond pneumatic circuit only when both the first leveling valve and thesecond leveling valve are set in a neutral mode such that each levelingvalve is neither supplying air from the one or more air supply tanks orremoving air into the atmosphere, wherein each of the first levelingvalve and the second leveling valve comprises: an upper housing mountedon a lower housing to form a valve body, wherein the valve body definesa chamber extending between the upper housing and the lower housing; thelower housing comprising a plurality of ports communicating with thechamber, wherein the plurality of ports include a supply port, anexhaust port, one or more spring ports, and a cross-flow port; a controlarm having a first end attached to a shaft extending through an uppersurface of the upper housing, wherein the control arm is configured torotate about the valve body in response to extension or compression ofthe vehicle suspension; a rotary disk positioned in the chamber of thevalve body and connected to the control arm by the shaft, wherein therotary disk is configured to rotate about the supporting element withinthe chamber of the valve body; and wherein the rotary disk is configuredto establish communication between the one or more spring ports and thecross-flow port while neither establishing communication between the oneor more spring ports and the supply port nor the one or more springports and the exhaust port.
 2. The method of claim 1, wherein the lowerhousing of each leveling valve comprises a dump port, wherein thecross-flow port is disposed on a first end of the lower housing and thedump port is disposed on a second end of the lower housing opposite tothe first end.
 3. The method of claim 1, wherein the control arm isconfigured to trigger movement of the valve element, wherein the valveelement is configured to move between a plurality of positions to altercommunication between the plurality of ports.
 4. The method of claim 3,wherein the plurality of positions include a neutral position toestablish pneumatic communication between the first and second pneumaticcircuits, a supply position to supply air from the one or more airsupply tanks to a respective pneumatic circuit, and an exhaust positionto remove air from the respective pneumatic circuit into the atmosphere.5. The method of claim 4, wherein the control arm is configured to pivotfrom a neutral position to one or more response positions, and eachleveling valve is set in the neutral mode when the control arm is set inthe neutral position, and each leveling valve is adjusting independentlythe air pressure of a respective pneumatic circuit when the control armis set to the one or more response positions.
 6. The method of claim 1,wherein the first pneumatic circuit comprises a first set of air springsdisposed on the first side of the vehicle, a first plurality of airlines pneumatically connecting the first set of air springs with thefirst leveling valve, and a first supply line pneumatically connectingthe first leveling valve with at least one of the one or more air supplytanks; and the second pneumatic circuit comprises a second set of airsprings disposed on the second side of the vehicle, a second pluralityof air lines pneumatically connecting the second set of air springs withthe second leveling valve, and a second supply line pneumaticallyconnecting the second leveling valve with at least one of the one ormore air supply tanks.
 7. The method of claim 1, wherein the control arminduces the rotary disk to rotate between a plurality of angularpositions to alter communication between the supply port, the exhaustport, the one or more spring ports, and the cross-flow port, wherein theplurality of angular positions include (i) a neutral position, in whichthe one or more spring ports pneumatically communicate with thecross-flow port, and neither the supply port nor the exhaust portpneumatically communicates with the one or more spring ports, (ii) asupply position, in which the one or more spring ports pneumaticallycommunicate with the supply port, and neither the exhaust port nor thecross-flow port pneumatically communicates with the one or more springports, and (iii) an exhaust position, in which the one or more springports pneumatically communicate with the exhaust port, and neither thesupply port nor the cross-flow port pneumatically communicates with theone or more spring ports.
 8. The method of claim 7, wherein the lowerhousing comprises a first surface mating with a lower surface of theupper housing, wherein the first surface defines a supply hole directlycommunicating with the supply port; an exhaust hole directlycommunicating with the exhaust port; a reservoir cavity directlycommunicating with the one or more spring ports.
 9. The method of claim8, wherein the rotary disk comprises a central aperture for receivingthe shaft, a plurality of oblong-shaped slots, and a cross-flow slot,wherein the plurality of oblong-shaped slots and cross-flow slot arespaced around the central aperture with dead band defined there betweenand along the periphery of the rotary disk.
 10. The method of claim 9,wherein each oblong-shaped cavity is configured to at least partiallyoverlie the reservoir cavity of the lower housing and the cross-flowslot over is configured to overlie the cross-flow hole of the lowerhousing when the rotary disk is set at the neutral position.
 11. Themethod of claim 9, wherein the oblong-shaped slots are symmetricallyspaced from a central axis extending along a face of the rotary disk,and the cross-flow slot overlies the central axis.
 12. The method ofclaim 1, wherein the supply port is disposed on a first side of thelower housing, and the exhaust port is disposed on a second side of thelower housing opposite to the first side of the lower housing.
 13. Themethod of claim 12, wherein the cross-flow port is disposed on a firstend of the lower housing, and the first end extends between the firstand second sides of the lower housing.
 14. The method of claim 12,wherein the one or more spring ports comprises a first spring sportlocated on one of the first side or the second side of the lowerhousing.
 15. An air management system for a vehicle, the air managementsystem comprising: a first pneumatic circuit having a first levelingvalve configured to adjust independently the height of a first side ofthe vehicle; a second pneumatic circuit having a second leveling valveconfigured to adjust independently the height of a second side of thevehicle; and a cross-flow line connecting the first leveling valve withthe second leveling valve; wherein the first and second leveling valvesare configured to establish pneumatic communication between the firstand second pneumatic circuits when the first leveling valve is notindependently adjusting the height of the first side of the vehicle andthe second leveling valve is not independently adjusting the height ofthe second side of the vehicle, wherein each of the first leveling valveand the second leveling valve comprises: an upper housing mounted on alower housing to form a valve body, wherein the valve body defines achamber extending between the upper housing and the lower housing; thelower housing comprising a plurality of ports communicating with thechamber, wherein the plurality of ports include a supply port, anexhaust port, one or more spring ports, and a cross-flow port; a controlarm having a first end attached to a shaft extending through an uppersurface of the upper housing, wherein the control arm is configured torotate about the valve body in response to extension or compression ofthe vehicle suspension; a rotary disk positioned in the chamber of thevalve body and connected to the control arm by the shaft, wherein therotary disk is configured to rotate about the supporting element withinthe chamber of the valve body; and wherein the rotary disk is configuredto establish communication between the one or more spring ports and thecross-flow port while neither establishing communication between the oneor more spring ports and the supply port nor the one or more springports and the exhaust port.
 16. The air management system of claim 15,wherein the control arm of each of the first and second leveling valvesis pivotably connected to the housing body, and the control arm isconfigured to pivot from a neutral position to one or more responsepositions.
 17. The air management system of claim 16, wherein controlarm of each of the first and second leveling valves is configured torotate about the valve in response to a height change by one of thefirst or second pneumatic circuits, and rotation of the control arminduces the rotary disk to rotate between a plurality of angularpositions to alter communication between the supply port, the exhaustport, the one or more spring ports, and the cross-flow port.
 18. The airmanagement system of claim 15, wherein the first and second levelingvalves are configured to establish pneumatic communication between thefirst and second pneumatic circuits when the control arm of both thefirst and second leveling valves are set in the neutral position, andthe first and second leveling valves are configured to prevent pneumaticcommunication between the first and second pneumatic circuits when thecontrol arm of one of the first and second leveling valves is set to theone or more response positions.
 19. The air management system of claim15, wherein the first pneumatic circuit comprises a first set of airsprings disposed on a first side of the vehicle, a first supply tank, afirst plurality of air lines pneumatically connecting the first set ofair springs with the first leveling valve, and a first supply linepneumatically connecting the first leveling valve with the first supplytank; and the second pneumatic circuit comprises a second set of airsprings disposed on a second side of the vehicle, a second supply tank,a second plurality of air lines pneumatically connecting the second setof air springs with the second leveling valve, and a second supply linepneumatically connecting the second leveling valve with the secondsupply tank.
 20. The air management system of claim 19, wherein thefirst plurality of air lines and the second plurality of air lines beingof the substantially the same diameter and length, and the first supplyline and the second supply line being of substantially the same diameterand length.